diff --git a/collects/compiler/private/xform.ss b/collects/compiler/private/xform.ss
index e8ebf358d8..f6037bef77 100644
--- a/collects/compiler/private/xform.ss
+++ b/collects/compiler/private/xform.ss
@@ -78,6 +78,8 @@
 	(hash-table-put! used-symbols (string->symbol "GC_get_variable_stack") 1)
 	(hash-table-put! used-symbols (string->symbol "GC_set_variable_stack") 1)
         (hash-table-put! used-symbols (string->symbol "memset") 1)
+	(hash-table-put! used-symbols (string->symbol "scheme_thread_local_key") 1)
+	(hash-table-put! used-symbols (string->symbol "pthread_getspecific") 1)
         
         ;; For dependency tracking:
         (define depends-files (make-hash-table 'equal))
@@ -587,6 +589,16 @@
                    (and (pragma? e)
                         (regexp-match #rx"GC_VARIABLE_STACK_THOUGH_TABLE" (pragma-s e))))
                  e-raw))
+        (define gc-var-stack-through-thread-local?
+          (ormap (lambda (e)
+                   (and (tok? e)
+                        (eq? (tok-n e) 'XFORM_GC_VARIABLE_STACK_THROUGH_THREAD_LOCAL)))
+                 e-raw))
+        (define gc-var-stack-through-getspecific?
+          (ormap (lambda (e)
+                   (and (tok? e)
+                        (eq? (tok-n e) 'XFORM_GC_VARIABLE_STACK_THROUGH_GETSPECIFIC)))
+                 e-raw))
         
         ;; The code produced by xform uses a number of macros. These macros
         ;; make the transformation about a little easier to debug, and they
@@ -595,9 +607,14 @@
         
         (when (and pgc? (not precompiled-header))
           ;; Setup GC_variable_stack macro
-          (printf (if gc-var-stack-through-table?
-                      "#define GC_VARIABLE_STACK (scheme_extension_table->GC_variable_stack)~n"
-                      "#define GC_VARIABLE_STACK GC_variable_stack~n"))
+          (printf (cond
+                   [gc-var-stack-through-table?
+                    "#define GC_VARIABLE_STACK (scheme_extension_table->GC_variable_stack)~n"]
+                   [gc-var-stack-through-getspecific?
+                    "#define GC_VARIABLE_STACK (((Thread_Local_Variables *)pthread_getspecific(scheme_thread_local_key))->GC_variable_stack_)~n"]
+                   [gc-var-stack-through-thread-local?
+                    "#define GC_VARIABLE_STACK ((&scheme_thread_locals)->GC_variable_stack_)~n"]
+                   [else "#define GC_VARIABLE_STACK GC_variable_stack~n"]))
 
           (if gc-variable-stack-through-funcs?
 	      (begin
@@ -713,8 +730,9 @@
           (printf "#define XFORM_OK_MINUS -~n")
           (printf "#define XFORM_TRUST_PLUS +~n")
           (printf "#define XFORM_TRUST_MINUS -~n")
+          (printf "#define XFORM_OK_ASSIGN /**/~n")
           (printf "~n")
-          
+
           ;; C++ cupport:
           (printf "#define NEW_OBJ(t) new (UseGC) t~n")
           (printf "#define NEW_ARRAY(t, array) (new (UseGC) t array)~n")
@@ -830,13 +848,14 @@
                \| \|\| & && |:| ? % + - * / ^ >> << ~ 
                #csXFORM_OK_PLUS #csXFORM_OK_MINUS #csXFORM_TRUST_PLUS #csXFORM_TRUST_MINUS 
                = >>= <<= ^= += *= /= -= %= \|= &= ++ --
-               return if for while else switch case
+               return if for while else switch case XFORM_OK_ASSIGN
                asm __asm __asm__ __volatile __volatile__ volatile __extension__
                __typeof sizeof __builtin_object_size
 
                ;; These don't act like functions:
                setjmp longjmp _longjmp scheme_longjmp_setjmp scheme_mz_longjmp scheme_jit_longjmp
                scheme_jit_setjmp_prepare
+               scheme_get_thread_local_variables pthread_getspecific
 
                ;; The following are functions, but they don't trigger GC, and
                ;; they either take one argument or no pointer arguments.
@@ -1053,7 +1072,10 @@
                 (set! non-pointer-types (list-ref l 5))
                 (set! struct-defs (list-ref l 6))
                 
-                (set! non-gcing-functions (hash-table-copy (list-ref l 7)))))))
+                (set! non-gcing-functions (hash-table-copy (list-ref l 7)))
+
+                (set! gc-var-stack-through-thread-local? (list-ref l 8))
+                (set! gc-var-stack-through-getspecific? (list-ref l 9))))))
         
         ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
         ;; Pretty-printing output
@@ -1160,6 +1182,7 @@
                      (unless (regexp-match re:boring s)
                        (printf "\n~a\n\n" s)
                        (set! line (+ line 3))))]
+                  [(threadlocal-decl? v) (void)]
                   [(seq? v)
                    (display/indent v (tok-n v))
                    (let ([subindent (if (braces? v)
@@ -1406,6 +1429,9 @@
             [(start-arith? e)
              (set! check-arith? #t)
              null]
+
+            [(threadlocal-decl? e)
+             null]
             
             [(access-modifier? e)
              ;; public, private, etc.
@@ -1580,6 +1606,11 @@
           (and (pair? e)
                (or (eq? END_XFORM_ARITH (tok-n (car e)))
                    (eq? 'XFORM_START_TRUST_ARITH (tok-n (car e))))))
+
+        (define (threadlocal-decl? e)
+          (and (pair? e)
+               (or (eq? 'XFORM_GC_VARIABLE_STACK_THROUGH_GETSPECIFIC (tok-n (car e)))
+                   (eq? 'XFORM_GC_VARIABLE_STACK_THROUGH_THREAD_LOCAL (tok-n (car e))))))
         
         (define (access-modifier? e)
           (and (memq (tok-n (car e)) '(public private protected))
@@ -1907,6 +1938,7 @@
                                                          (and struct-array?
                                                               (struct-array-type-count (cdr base-is-ptr?))))])
                                     (when (and struct-array?
+                                               (not union-ok?)
                                                (> array-size 16))
                                       (log-error "[SIZE] ~a in ~a: Large array of structures at ~a."
                                                  (tok-line v) (tok-file v) name))
@@ -3553,7 +3585,10 @@
                                                               (and m
                                                                    (not (or (array-type? (cdr m))
                                                                             (struct-array-type? (cdr m)))))))))
-                                                  (not (symbol? (tok-n (car assignee)))))
+                                                  (and (not (symbol? (tok-n (car assignee))))
+                                                       ;; as below, ok if preceded by XFORM_OK_ASSIGN
+                                                       (or (not (pair? (cdr assignee)))
+                                                           (not (eq? (tok-n (cadr assignee)) 'XFORM_OK_ASSIGN)))))
                                               (and (symbol? (tok-n (car assignee)))
                                                    (not (null? (cdr assignee)))
                                                    ;; ok if name starts with "_stk_"
@@ -3565,6 +3600,8 @@
                                                              (pair? (cddr assignee))
                                                              (symbol? (tok-n (caddr assignee)))
                                                              (null? (cdddr assignee))))
+                                                   ;; ok if preceded by XFORM_OK_ASSIGN
+                                                   (not (eq? (tok-n (cadr assignee)) 'XFORM_OK_ASSIGN))
                                                    ;; ok if preceeding is `if', `until', etc.
                                                    (not (and (parens? (cadr assignee))
                                                              (pair? (cddr assignee))
@@ -3964,7 +4001,9 @@
                     (marshall pointer-types)
                     (marshall non-pointer-types)
                     (marshall struct-defs)
-		    non-gcing-functions)])
+		    non-gcing-functions
+                    gc-var-stack-through-thread-local?
+                    gc-var-stack-through-getspecific?)])
               (with-output-to-file (change-suffix file-out #".zo")
                 (lambda ()
                   (let ([orig (current-namespace)])
diff --git a/src/mzscheme/gc2/Makefile.in b/src/mzscheme/gc2/Makefile.in
index 0a1a9a1211..13d638b17b 100644
--- a/src/mzscheme/gc2/Makefile.in
+++ b/src/mzscheme/gc2/Makefile.in
@@ -138,7 +138,7 @@ xobjects: $(OBJS) main.@LTO@
 XFORMDEP = $(srcdir)/gc2.h $(srcdir)/gc2_obj.h $(srcdir)/xform.ss $(srcdir)/xform-mod.ss \
            $(srcdir)/precomp.c $(srcdir)/../src/schpriv.h $(srcdir)/../include/scheme.h \
            $(srcdir)/../sconfig.h $(srcdir)/../uconfig.h $(srcdir)/../src/schemef.h \
-           $(srcdir)/../src/stypes.h 
+           $(srcdir)/../src/stypes.h $(srcdir)/../include/schthread.h 
 
 LIGHTNINGDEP = $(srcdir)/../src/lightning/i386/core.h $(srcdir)/../src/lightning/i386/core-common.h \
                $(srcdir)/../src/lightning/i386/asm.h $(srcdir)/../src/lightning/i386/asm-common.h \
diff --git a/src/mzscheme/gc2/gc2.h b/src/mzscheme/gc2/gc2.h
index e197680ab3..043ed933c4 100644
--- a/src/mzscheme/gc2/gc2.h
+++ b/src/mzscheme/gc2/gc2.h
@@ -2,16 +2,6 @@
 #ifndef __mzscheme_gc_2__
 #define __mzscheme_gc_2__
 
-#if defined(MZ_USE_PLACES) || defined(FUTURES_ENABLED)
-# if _MSC_VER
-#  define THREAD_LOCAL __declspec(thread)
-# else
-#  define THREAD_LOCAL __thread
-# endif
-#else
-# define THREAD_LOCAL /* empty */
-#endif
-
 /***************************************************************************/
 /***   See README for a general overview of the interface architecture.  ***/
 /***************************************************************************/
@@ -288,7 +278,7 @@ GC2_EXTERN void GC_finalization_weak_ptr(void **p, int offset);
 /* Cooperative GC                                                          */
 /***************************************************************************/
 
-GC2_EXTERN THREAD_LOCAL void **GC_variable_stack;
+THREAD_LOCAL_DECL(GC2_EXTERN void **GC_variable_stack);
 /*
    See the general overview in README. */
 
diff --git a/src/mzscheme/gc2/gc2_obj.h b/src/mzscheme/gc2/gc2_obj.h
index be0b6a6dbf..31743a6d57 100644
--- a/src/mzscheme/gc2/gc2_obj.h
+++ b/src/mzscheme/gc2/gc2_obj.h
@@ -1,4 +1,5 @@
-#include "../src/schpriv.h"
+#ifndef GC2_OBJHEAD_H
+#define GC2_OBJHEAD_H
 
 #if defined(MZ_PRECISE_GC) && !defined(USE_COMPACT_3M_GC)
 
@@ -34,3 +35,5 @@ XFORM_NONGCING extern int GC_is_allocated(void *p);
 #define OBJHEAD_HASH_BITS(p) (OBJPTR_TO_OBJHEAD(p)->hash)
 
 #endif
+
+#endif
diff --git a/src/mzscheme/gc2/newgc.c b/src/mzscheme/gc2/newgc.c
index 87a9e98bbe..7955f2f853 100644
--- a/src/mzscheme/gc2/newgc.c
+++ b/src/mzscheme/gc2/newgc.c
@@ -27,13 +27,16 @@
    the nursery and pages being compacted.
 */
 
-#define MZ_PRECISE_GC 1 /* required for mz includes to work right */
+#define MZ_PRECISE_GC /* required for mz includes to work right */
+#define XFORM_OK_ASSIGN /* annotation used when thread-local variables are needed */
+#define SKIP_THREAD_LOCAL_XFORM_DECL
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>
 #include "pthread.h"
 #include "platforms.h"
+#include "../src/schpriv.h"
 #include "gc2.h"
 #include "gc2_dump.h" 
 
@@ -98,9 +101,9 @@ static const char *type_name[PAGE_TYPES] = {
 #ifdef MZ_USE_PLACES
 static NewGC *MASTERGC;
 static NewGCMasterInfo *MASTERGCINFO;
-static THREAD_LOCAL objhead GC_objhead_template;
+THREAD_LOCAL_DECL(static objhead GC_objhead_template);
 #endif
-static THREAD_LOCAL NewGC *GC;
+THREAD_LOCAL_DECL(static NewGC *GC);
 #define GCTYPE NewGC
 #define GC_get_GC() (GC)
 #define GC_set_GC(gc) (GC = gc)
@@ -471,8 +474,8 @@ int GC_is_allocated(void *p)
    The size count helps us trigger collection quickly when we're running out of space; see
    the test in allocate_big. 
 */
-THREAD_LOCAL unsigned long GC_gen0_alloc_page_ptr = 0;
-THREAD_LOCAL unsigned long GC_gen0_alloc_page_end = 0;
+THREAD_LOCAL_DECL(unsigned long GC_gen0_alloc_page_ptr = 0);
+THREAD_LOCAL_DECL(unsigned long GC_gen0_alloc_page_end = 0);
 
 /* miscellaneous variables */
 static const char *zero_sized[4]; /* all 0-sized allocs get this */
@@ -1242,7 +1245,7 @@ static void *get_backtrace(mpage *page, void *ptr)
 /* With the exception of the "traverse" macro and resultant simplification,  */
 /* this code is entirely lifted from compact.c                               */
 /*****************************************************************************/
-THREAD_LOCAL void **GC_variable_stack;
+THREAD_LOCAL_DECL(void **GC_variable_stack);
 
 void **GC_get_variable_stack()
 { 
@@ -1514,7 +1517,7 @@ inline static void reset_weak_finalizers(NewGC *gc)
 #define MARK_STACK_START(ms) ((void **)(void *)&ms[1])
 #define MARK_STACK_END(ms) ((void **)((char *)ms + STACK_PART_SIZE))
 
-static THREAD_LOCAL MarkSegment *mark_stack = NULL;
+THREAD_LOCAL_DECL(static MarkSegment *mark_stack = NULL);
 
 inline static MarkSegment* mark_stack_create_frame() {
   MarkSegment *mark_frame = (MarkSegment*)ofm_malloc(STACK_PART_SIZE);
diff --git a/src/mzscheme/gc2/vm_osx.c b/src/mzscheme/gc2/vm_osx.c
index 93ea4a2b17..9d1e9afca0 100644
--- a/src/mzscheme/gc2/vm_osx.c
+++ b/src/mzscheme/gc2/vm_osx.c
@@ -250,12 +250,16 @@ kern_return_t catch_exception_raise(mach_port_t port,
 /* this is the thread which forwards of exceptions read from the exception
    server off to our exception catchers and then back out to the other
    thread */
-void exception_thread(void)
+void exception_thread(void *shared_thread_state)
 {
   mach_msg_header_t *message;
   mach_msg_header_t *reply;
   kern_return_t retval;
-  
+
+#ifdef USE_THREAD_LOCAL
+  pthread_setspecific(scheme_thread_local_key, shared_thread_state);
+#endif
+
   /* allocate the space for the message and reply */
   message = (mach_msg_header_t*)malloc(sizeof(mach_exc_msg_t));
   reply = (mach_msg_header_t*)malloc(sizeof(mach_reply_msg_t));
@@ -313,8 +317,7 @@ static void macosx_init_exception_handler()
   }
 
 #ifdef PPC_HAND_ROLLED_THREAD 
-  /* Old hand-rolled thread creation. pthread_create is fine for our
-     purposes. */
+  /* Old hand-rolled thread creation. */
  {
    /* set up the subthread */
    mach_port_t exc_thread;
@@ -347,7 +350,11 @@ static void macosx_init_exception_handler()
 #else
  {
    pthread_t th;
-   pthread_create(&th, NULL, (void *(*)(void *))exception_thread, NULL);
+   void *data = NULL;
+#ifdef USE_THREAD_LOCAL
+   data = pthread_getspecific(scheme_thread_local_key);
+#endif
+   pthread_create(&th, NULL, (void *(*)(void *))exception_thread, data);
  }
 #endif
 }
diff --git a/src/mzscheme/include/gmzwin.def b/src/mzscheme/include/gmzwin.def
index f0136f8eb8..50845744cf 100644
--- a/src/mzscheme/include/gmzwin.def
+++ b/src/mzscheme/include/gmzwin.def
@@ -3,3 +3,8 @@ EXPORTS
  GC_malloc_atomic
  GC_malloc_stubborn
  GC_malloc_uncollectable
+ GC_register_traversers
+ GC_resolve
+ GC_mark
+ GC_fixup
+ GC_fixup_self
diff --git a/src/mzscheme/include/mzscheme.exp b/src/mzscheme/include/mzscheme.exp
index 6441f54693..ff78581700 100644
--- a/src/mzscheme/include/mzscheme.exp
+++ b/src/mzscheme/include/mzscheme.exp
@@ -202,6 +202,11 @@ scheme_remove_all_finalization
 scheme_dont_gc_ptr
 scheme_gc_ptr_ok
 scheme_collect_garbage
+GC_register_traversers
+GC_resolve
+GC_mark
+GC_fixup
+GC_fixup_self
 scheme_malloc_immobile_box
 scheme_free_immobile_box
 scheme_make_bucket_table
diff --git a/src/mzscheme/include/scheme.h b/src/mzscheme/include/scheme.h
index f8e52208ac..4b981e858f 100644
--- a/src/mzscheme/include/scheme.h
+++ b/src/mzscheme/include/scheme.h
@@ -166,16 +166,6 @@ typedef struct FSSpec mzFSSpec;
 
 #define MZ_EXTERN extern MZ_DLLSPEC
 
-#if defined(MZ_USE_PLACES) || defined(FUTURES_ENABLED)
-# if _MSC_VER
-#  define THREAD_LOCAL __declspec(thread)
-# else
-#  define THREAD_LOCAL __thread
-# endif
-#else
-# define THREAD_LOCAL /* empty */
-#endif
-
 #ifndef MZ_DONT_USE_JIT
 # if defined(MZ_USE_JIT_PPC) || defined(MZ_USE_JIT_I386) || defined(MZ_USE_JIT_X86_64)
 #  define MZ_USE_JIT
@@ -908,6 +898,11 @@ typedef struct Scheme_Cont_Frame_Data {
 /*                              threads                                   */
 /*========================================================================*/
 
+#ifdef MZ_PRECISE_GC
+# include "../gc2/gc2_obj.h"
+#endif
+#include "schthread.h"
+
 typedef void (Scheme_Close_Custodian_Client)(Scheme_Object *o, void *data);
 typedef void (*Scheme_Exit_Closer_Func)(Scheme_Object *, Scheme_Close_Custodian_Client *, void *);
 typedef Scheme_Object *(*Scheme_Custodian_Extractor)(Scheme_Object *o);
@@ -1492,7 +1487,7 @@ typedef void (*Scheme_Invoke_Proc)(Scheme_Env *env, long phase_shift,
 #  define scheme_fuel_counter (*scheme_fuel_counter_ptr)
 # endif
 #else
-MZ_EXTERN THREAD_LOCAL volatile int scheme_fuel_counter;
+THREAD_LOCAL_DECL(MZ_EXTERN volatile int scheme_fuel_counter);
 #endif
 
 #ifdef FUEL_AUTODECEREMENTS
@@ -1701,8 +1696,8 @@ MZ_EXTERN void scheme_set_logging(int syslog_level, int stderr_level);
 MZ_EXTERN int scheme_get_allow_set_undefined();
 
 #ifndef MZ_USE_PLACES
-MZ_EXTERN THREAD_LOCAL Scheme_Thread *scheme_current_thread;
-MZ_EXTERN THREAD_LOCAL Scheme_Thread *scheme_first_thread;
+THREAD_LOCAL_DECL(MZ_EXTERN Scheme_Thread *scheme_current_thread);
+THREAD_LOCAL_DECL(MZ_EXTERN Scheme_Thread *scheme_first_thread);
 #endif
 MZ_EXTERN Scheme_Thread *scheme_get_current_thread();
 MZ_EXTERN long scheme_get_multiple_count();
diff --git a/src/mzscheme/include/schthread.h b/src/mzscheme/include/schthread.h
new file mode 100644
index 0000000000..b640482edc
--- /dev/null
+++ b/src/mzscheme/include/schthread.h
@@ -0,0 +1,362 @@
+
+/* Implements thread-local variables, which are all combined into one
+   big table.
+   
+   When thread-local variables are not needed, this file doesn't
+   declare them. Instead, declarations marked with
+   THREAD_LOCAL_DECL() are used.
+
+   When thread-local variables are needed, then THREAD_LOCAL_DECL()
+   expands to nothing, and this file defines each thread-local variable
+   as a field in one big record. The record is accessed through a single
+   thread-local variable or through pthread_getspecific().
+
+   Choose the names of thread-local variables carefully. The names are
+   globally visible, and macros to redirect uses of thread-local
+   variables can create trouble and poor error messages from the C
+   compiler if the same name is used for a local variable. */
+
+#ifndef SCHEME_THREADLOCAL_H
+#define SCHEME_THREADLOCAL_H
+
+#if defined(MZ_USE_PLACES) || defined(FUTURES_ENABLED)
+#  define USE_THREAD_LOCAL
+# if _MSC_VER
+#  define THREAD_LOCAL __declspec(thread)
+# elif defined(OS_X)
+#  define IMPLEMENT_THREAD_LOCAL_VIA_PTHREADS
+# else
+#  define THREAD_LOCAL __thread
+# endif
+#else
+# define THREAD_LOCAL /* empty */
+#endif
+
+extern void scheme_init_os_thread();
+
+/* **************************************************************** */
+/* Declarations that we wish were elsewhere, but are needed here to */
+/* determine the size and type of some thread-local record fields.  */
+/* **************************************************************** */
+
+#define STACK_COPY_CACHE_SIZE 10
+#define BIGNUM_CACHE_SIZE 16
+#define NUM_tl_VARS 14
+#define STACK_CACHE_SIZE 32
+
+/* This structure must be 4 words: */
+typedef struct {
+  void *orig_return_address;
+  void *stack_frame;
+  struct Scheme_Object *cache;
+  void *orig_result;
+} Stack_Cache_Elem;
+
+typedef long rxpos;
+
+#ifndef MZ_PRECISE_GC
+typedef long objhead;
+#endif
+
+/* **************************************** */
+
+#ifndef USE_THREAD_LOCAL
+
+# define THREAD_LOCAL_DECL(x) x
+
+#else
+
+/* **************************************** */
+
+typedef struct Thread_Local_Variables {
+  void **GC_variable_stack_;
+  objhead GC_objhead_template_;
+  struct NewGC *GC_;
+  unsigned long GC_gen0_alloc_page_ptr_;
+  unsigned long GC_gen0_alloc_page_end_;
+  struct MarkSegment *mark_stack_;
+  void *bignum_cache_[BIGNUM_CACHE_SIZE];
+  int cache_count_;
+  struct Scheme_Hash_Table *toplevels_ht_;
+  struct Scheme_Hash_Table *locals_ht_[2];
+  volatile int scheme_fuel_counter_;
+  unsigned long scheme_stack_boundary_;
+  unsigned long volatile scheme_jit_stack_boundary_;
+  struct Scheme_Object *quick_stx_;
+  int scheme_continuation_application_count_;
+  int scheme_cont_capture_count_;
+  int scheme_prompt_capture_count_;
+  struct Scheme_Prompt *available_prompt_;
+  struct Scheme_Prompt *available_cws_prompt_;
+  struct Scheme_Prompt *available_regular_prompt_;
+  struct Scheme_Dynamic_Wind *available_prompt_dw_;
+  struct Scheme_Meta_Continuation *available_prompt_mc_;
+  struct Scheme_Object *cached_beg_stx_;
+  struct Scheme_Object *cached_dv_stx_;
+  struct Scheme_Object *cached_ds_stx_;
+  int cached_stx_phase_;
+  struct Scheme_Cont *offstack_cont_;
+  struct Scheme_Overflow *offstack_overflow_;
+  struct Scheme_Overflow_Jmp *scheme_overflow_jmp_;
+  void *scheme_overflow_stack_start_;
+  struct future_t *current_ft_;
+  void **codetab_tree_;
+  int during_set_;
+  void *thread_local_pointers_[NUM_tl_VARS];
+  Stack_Cache_Elem stack_cache_stack_[STACK_CACHE_SIZE];
+  long stack_cache_stack_pos_;
+  struct Scheme_Object **fixup_runstack_base_;
+  int fixup_already_in_place_;
+  void *retry_alloc_r1_;
+  double save_fp_;
+  struct Scheme_Bucket_Table *starts_table_;
+  struct Scheme_Modidx *modidx_caching_chain_;
+  struct Scheme_Object *global_shift_cache_;
+  struct mz_proc_thread *proc_thread_self_;
+  struct Scheme_Object *scheme_orig_stdout_port_;
+  struct Scheme_Object *scheme_orig_stderr_port_;
+  struct Scheme_Object *scheme_orig_stdin_port_;
+  struct fd_set *scheme_fd_set_;
+  struct Scheme_Custodian *new_port_cust_;
+  int external_event_fd_;
+  int put_external_event_fd_;
+  char *read_string_byte_buffer_;
+  struct ITimer_Data *itimerdata_;
+  char *quick_buffer_;
+  char *quick_encode_buffer_;
+  struct Scheme_Hash_Table *cache_ht_;
+  char *regstr_;
+  char *regparsestr_;
+  int regmatchmin_;
+  int regmatchmax_;
+  int regmaxbackposn_;
+  int regsavepos_;
+  struct Scheme_Hash_Table *regbackknown_;
+  struct Scheme_Hash_Table *regbackdepends_;
+  rxpos regparse_;
+  rxpos regparse_end_;
+  int regnpar_;
+  int regncounter_;
+  rxpos regcode_;
+  rxpos regcodesize_;
+  rxpos regcodemax_;
+  long regmaxlookback_;
+  long rx_buffer_size_;
+  rxpos *startp_buffer_cache_;
+  rxpos *endp_buffer_cache_;
+  rxpos *maybep_buffer_cache_;
+  unsigned long scheme_os_thread_stack_base_;
+  int traversers_registered_;
+  struct Finalizations **save_fns_ptr_;
+  struct Scheme_Object *scheme_system_idle_channel_;
+  struct Scheme_Object *system_idle_put_evt_;
+  void *stack_copy_cache_[STACK_COPY_CACHE_SIZE];
+  long stack_copy_size_cache_[STACK_COPY_CACHE_SIZE];
+  int scc_pos_;
+  struct Scheme_Bucket_Table *prefab_table_;
+  struct Scheme_Object *nominal_ipair_cache_;
+  struct Scheme_Object *mark_id_;
+  struct Scheme_Object *current_rib_timestamp_;
+  struct Scheme_Hash_Table *quick_hash_table_;
+  struct Scheme_Object *last_phase_shift_;
+  struct Scheme_Object *unsealed_dependencies_;
+  struct Scheme_Hash_Table *id_marks_ht_;
+  struct Scheme_Hash_Table *than_id_marks_ht_;
+  struct Scheme_Bucket_Table *interned_skip_ribs_;
+  struct Scheme_Thread *scheme_current_thread_;
+  struct Scheme_Thread *scheme_main_thread_;
+  struct Scheme_Thread *scheme_first_thread_;
+  struct Scheme_Thread_Set *scheme_thread_set_top_;
+  int num_running_threads_;
+  int swap_no_setjmp_;
+  int thread_swap_count_;
+  int did_gc_count_;
+  struct Scheme_Object **scheme_current_runstack_start_;
+  struct Scheme_Object **scheme_current_runstack_;
+  MZ_MARK_STACK_TYPE scheme_current_cont_mark_stack_;
+  MZ_MARK_POS_TYPE scheme_current_cont_mark_pos_;
+  struct Scheme_Custodian *main_custodian_;
+  struct Scheme_Custodian *last_custodian_;
+  struct Scheme_Hash_Table *limited_custodians_;
+  struct Scheme_Thread *swap_target_;
+  struct Scheme_Object *scheduled_kills_;
+  int do_atomic_;
+  int missed_context_switch_;
+  int have_activity_;
+  int scheme_active_but_sleeping_;
+  int thread_ended_with_activity_;
+  int scheme_no_stack_overflow_;
+  int needs_sleep_cancelled_;
+  int tls_pos_;
+  struct Scheme_Object *the_nested_exn_handler_;
+  struct Scheme_Object *cust_closers_;
+  struct Scheme_Object *thread_swap_callbacks_;
+  struct Scheme_Object *thread_swap_out_callbacks_;
+  struct Scheme_Object *recycle_cell_;
+  struct Scheme_Object *maybe_recycle_cell_;
+  int recycle_cc_count_;
+  mz_jmp_buf main_init_error_buf_;
+} Thread_Local_Variables;
+
+#if defined(IMPLEMENT_THREAD_LOCAL_VIA_PTHREADS)
+/* Using Pthread getspecific() */
+# include <pthread.h>
+MZ_EXTERN pthread_key_t scheme_thread_local_key;
+# define scheme_get_thread_local_variables() ((Thread_Local_Variables *)pthread_getspecific(scheme_thread_local_key))
+# if defined(MZ_PRECISE_GC) && !defined(SKIP_THREAD_LOCAL_XFORM_DECL)
+XFORM_GC_VARIABLE_STACK_THROUGH_GETSPECIFIC;
+# endif
+#else
+/* Using `THREAD_LOCAL' variable: */
+MZ_EXTERN THREAD_LOCAL Thread_Local_Variables scheme_thread_locals;
+# define scheme_get_thread_local_variables() (&scheme_thread_locals)
+# if defined(MZ_PRECISE_GC) && !defined(SKIP_THREAD_LOCAL_XFORM_DECL)
+XFORM_GC_VARIABLE_STACK_THROUGH_THREAD_LOCAL;
+# endif
+#endif
+
+/* **************************************** */
+
+#ifdef MZ_PRECISE_GC
+# define XOA XFORM_OK_ASSIGN
+#else
+# define XOA /* empty */
+#endif
+
+#define GC_objhead_template XOA (scheme_get_thread_local_variables()->GC_objhead_template_)
+#define GC XOA (scheme_get_thread_local_variables()->GC_)
+#define GC_gen0_alloc_page_ptr XOA (scheme_get_thread_local_variables()->GC_gen0_alloc_page_ptr_)
+#define GC_gen0_alloc_page_end XOA (scheme_get_thread_local_variables()->GC_gen0_alloc_page_end_)
+#define GC_variable_stack XOA (scheme_get_thread_local_variables()->GC_variable_stack_)
+#define mark_stack XOA (scheme_get_thread_local_variables()->mark_stack_)
+#define bignum_cache XOA (scheme_get_thread_local_variables()->bignum_cache_)
+#define cache_count XOA (scheme_get_thread_local_variables()->cache_count_)
+#define toplevels_ht XOA (scheme_get_thread_local_variables()->toplevels_ht_)
+#define locals_ht XOA (scheme_get_thread_local_variables()->locals_ht_)
+#define scheme_fuel_counter XOA (scheme_get_thread_local_variables()->scheme_fuel_counter_)
+#define scheme_stack_boundary XOA (scheme_get_thread_local_variables()->scheme_stack_boundary_)
+#define scheme_jit_stack_boundary XOA (scheme_get_thread_local_variables()->scheme_jit_stack_boundary_)
+#define quick_stx XOA (scheme_get_thread_local_variables()->quick_stx_)
+#define scheme_continuation_application_count XOA (scheme_get_thread_local_variables()->scheme_continuation_application_count_)
+#define scheme_cont_capture_count XOA (scheme_get_thread_local_variables()->scheme_cont_capture_count_)
+#define scheme_prompt_capture_count XOA (scheme_get_thread_local_variables()->scheme_prompt_capture_count_)
+#define available_prompt XOA (scheme_get_thread_local_variables()->available_prompt_)
+#define available_cws_prompt XOA (scheme_get_thread_local_variables()->available_cws_prompt_)
+#define available_regular_prompt XOA (scheme_get_thread_local_variables()->available_regular_prompt_)
+#define available_prompt_dw XOA (scheme_get_thread_local_variables()->available_prompt_dw_)
+#define available_prompt_mc XOA (scheme_get_thread_local_variables()->available_prompt_mc_)
+#define cached_beg_stx XOA (scheme_get_thread_local_variables()->cached_beg_stx_)
+#define cached_dv_stx XOA (scheme_get_thread_local_variables()->cached_dv_stx_)
+#define cached_ds_stx XOA (scheme_get_thread_local_variables()->cached_ds_stx_)
+#define cached_stx_phase XOA (scheme_get_thread_local_variables()->cached_stx_phase_)
+#define offstack_cont XOA (scheme_get_thread_local_variables()->offstack_cont_)
+#define offstack_overflow XOA (scheme_get_thread_local_variables()->offstack_overflow_)
+#define scheme_overflow_jmp XOA (scheme_get_thread_local_variables()->scheme_overflow_jmp_)
+#define scheme_overflow_stack_start XOA (scheme_get_thread_local_variables()->scheme_overflow_stack_start_)
+#define current_ft XOA (scheme_get_thread_local_variables()->current_ft_)
+#define codetab_tree XOA (scheme_get_thread_local_variables()->codetab_tree_)
+#define during_set XOA (scheme_get_thread_local_variables()->during_set_)
+#define thread_local_pointers XOA (scheme_get_thread_local_variables()->thread_local_pointers_)
+#define stack_cache_stack XOA (scheme_get_thread_local_variables()->stack_cache_stack_)
+#define stack_cache_stack_pos XOA (scheme_get_thread_local_variables()->stack_cache_stack_pos_)
+#define fixup_runstack_base XOA (scheme_get_thread_local_variables()->fixup_runstack_base_)
+#define fixup_already_in_place XOA (scheme_get_thread_local_variables()->fixup_already_in_place_)
+#define retry_alloc_r1 XOA (scheme_get_thread_local_variables()->retry_alloc_r1_)
+#define save_fp XOA (scheme_get_thread_local_variables()->save_fp_)
+#define starts_table XOA (scheme_get_thread_local_variables()->starts_table_)
+#define modidx_caching_chain XOA (scheme_get_thread_local_variables()->modidx_caching_chain_)
+#define global_shift_cache XOA (scheme_get_thread_local_variables()->global_shift_cache_)
+#define proc_thread_self XOA (scheme_get_thread_local_variables()->proc_thread_self_)
+#define scheme_orig_stdout_port XOA (scheme_get_thread_local_variables()->scheme_orig_stdout_port_)
+#define scheme_orig_stderr_port XOA (scheme_get_thread_local_variables()->scheme_orig_stderr_port_)
+#define scheme_orig_stdin_port XOA (scheme_get_thread_local_variables()->scheme_orig_stdin_port_)
+#define scheme_fd_set XOA (scheme_get_thread_local_variables()->scheme_fd_set_)
+#define new_port_cust XOA (scheme_get_thread_local_variables()->new_port_cust_)
+#define external_event_fd XOA (scheme_get_thread_local_variables()->external_event_fd_)
+#define put_external_event_fd XOA (scheme_get_thread_local_variables()->put_external_event_fd_)
+#define read_string_byte_buffer XOA (scheme_get_thread_local_variables()->read_string_byte_buffer_)
+#define itimerdata XOA (scheme_get_thread_local_variables()->itimerdata_)
+#define quick_buffer XOA (scheme_get_thread_local_variables()->quick_buffer_)
+#define quick_encode_buffer XOA (scheme_get_thread_local_variables()->quick_encode_buffer_)
+#define cache_ht XOA (scheme_get_thread_local_variables()->cache_ht_)
+#define regstr XOA (scheme_get_thread_local_variables()->regstr_)
+#define regparsestr XOA (scheme_get_thread_local_variables()->regparsestr_)
+#define regmatchmin XOA (scheme_get_thread_local_variables()->regmatchmin_)
+#define regmatchmax XOA (scheme_get_thread_local_variables()->regmatchmax_)
+#define regmaxbackposn XOA (scheme_get_thread_local_variables()->regmaxbackposn_)
+#define regsavepos XOA (scheme_get_thread_local_variables()->regsavepos_)
+#define regbackknown XOA (scheme_get_thread_local_variables()->regbackknown_)
+#define regbackdepends XOA (scheme_get_thread_local_variables()->regbackdepends_)
+#define regparse XOA (scheme_get_thread_local_variables()->regparse_)
+#define regparse_end XOA (scheme_get_thread_local_variables()->regparse_end_)
+#define regnpar XOA (scheme_get_thread_local_variables()->regnpar_)
+#define regncounter XOA (scheme_get_thread_local_variables()->regncounter_)
+#define regcode XOA (scheme_get_thread_local_variables()->regcode_)
+#define regcodesize XOA (scheme_get_thread_local_variables()->regcodesize_)
+#define regcodemax XOA (scheme_get_thread_local_variables()->regcodemax_)
+#define regmaxlookback XOA (scheme_get_thread_local_variables()->regmaxlookback_)
+#define rx_buffer_size XOA (scheme_get_thread_local_variables()->rx_buffer_size_)
+#define startp_buffer_cache XOA (scheme_get_thread_local_variables()->startp_buffer_cache_)
+#define endp_buffer_cache XOA (scheme_get_thread_local_variables()->endp_buffer_cache_)
+#define maybep_buffer_cache XOA (scheme_get_thread_local_variables()->maybep_buffer_cache_)
+#define scheme_os_thread_stack_base XOA (scheme_get_thread_local_variables()->scheme_os_thread_stack_base_)
+#define traversers_registered XOA (scheme_get_thread_local_variables()->traversers_registered_)
+#define save_fns_ptr XOA (scheme_get_thread_local_variables()->save_fns_ptr_)
+#define scheme_system_idle_channel XOA (scheme_get_thread_local_variables()->scheme_system_idle_channel_)
+#define system_idle_put_evt XOA (scheme_get_thread_local_variables()->system_idle_put_evt_)
+#define stack_copy_cache XOA (scheme_get_thread_local_variables()->stack_copy_cache_)
+#define stack_copy_size_cache XOA (scheme_get_thread_local_variables()->stack_copy_size_cache_)
+#define scc_pos XOA (scheme_get_thread_local_variables()->scc_pos_)
+#define prefab_table XOA (scheme_get_thread_local_variables()->prefab_table_)
+#define nominal_ipair_cache XOA (scheme_get_thread_local_variables()->nominal_ipair_cache_)
+#define mark_id XOA (scheme_get_thread_local_variables()->mark_id_)
+#define current_rib_timestamp XOA (scheme_get_thread_local_variables()->current_rib_timestamp_)
+#define quick_hash_table XOA (scheme_get_thread_local_variables()->quick_hash_table_)
+#define last_phase_shift XOA (scheme_get_thread_local_variables()->last_phase_shift_)
+#define unsealed_dependencies XOA (scheme_get_thread_local_variables()->unsealed_dependencies_)
+#define id_marks_ht XOA (scheme_get_thread_local_variables()->id_marks_ht_)
+#define than_id_marks_ht XOA (scheme_get_thread_local_variables()->than_id_marks_ht_)
+#define interned_skip_ribs XOA (scheme_get_thread_local_variables()->interned_skip_ribs_)
+#define scheme_current_thread XOA (scheme_get_thread_local_variables()->scheme_current_thread_)
+#define scheme_main_thread XOA (scheme_get_thread_local_variables()->scheme_main_thread_)
+#define scheme_first_thread XOA (scheme_get_thread_local_variables()->scheme_first_thread_)
+#define scheme_thread_set_top XOA (scheme_get_thread_local_variables()->scheme_thread_set_top_)
+#define num_running_threads XOA (scheme_get_thread_local_variables()->num_running_threads_)
+#define swap_no_setjmp XOA (scheme_get_thread_local_variables()->swap_no_setjmp_)
+#define thread_swap_count XOA (scheme_get_thread_local_variables()->thread_swap_count_)
+#define did_gc_count XOA (scheme_get_thread_local_variables()->did_gc_count_)
+#define scheme_current_runstack_start XOA (scheme_get_thread_local_variables()->scheme_current_runstack_start_)
+#define scheme_current_runstack XOA (scheme_get_thread_local_variables()->scheme_current_runstack_)
+#define scheme_current_cont_mark_stack XOA (scheme_get_thread_local_variables()->scheme_current_cont_mark_stack_)
+#define scheme_current_cont_mark_pos XOA (scheme_get_thread_local_variables()->scheme_current_cont_mark_pos_)
+#define main_custodian XOA (scheme_get_thread_local_variables()->main_custodian_)
+#define last_custodian XOA (scheme_get_thread_local_variables()->last_custodian_)
+#define limited_custodians XOA (scheme_get_thread_local_variables()->limited_custodians_)
+#define swap_target XOA (scheme_get_thread_local_variables()->swap_target_)
+#define scheduled_kills XOA (scheme_get_thread_local_variables()->scheduled_kills_)
+#define do_atomic XOA (scheme_get_thread_local_variables()->do_atomic_)
+#define missed_context_switch XOA (scheme_get_thread_local_variables()->missed_context_switch_)
+#define have_activity XOA (scheme_get_thread_local_variables()->have_activity_)
+#define scheme_active_but_sleeping XOA (scheme_get_thread_local_variables()->scheme_active_but_sleeping_)
+#define thread_ended_with_activity XOA (scheme_get_thread_local_variables()->thread_ended_with_activity_)
+#define scheme_no_stack_overflow XOA (scheme_get_thread_local_variables()->scheme_no_stack_overflow_)
+#define needs_sleep_cancelled XOA (scheme_get_thread_local_variables()->needs_sleep_cancelled_)
+#define tls_pos XOA (scheme_get_thread_local_variables()->tls_pos_)
+#define the_nested_exn_handler XOA (scheme_get_thread_local_variables()->the_nested_exn_handler_)
+#define cust_closers XOA (scheme_get_thread_local_variables()->cust_closers_)
+#define thread_swap_callbacks XOA (scheme_get_thread_local_variables()->thread_swap_callbacks_)
+#define thread_swap_out_callbacks XOA (scheme_get_thread_local_variables()->thread_swap_out_callbacks_)
+#define recycle_cell XOA (scheme_get_thread_local_variables()->recycle_cell_)
+#define maybe_recycle_cell XOA (scheme_get_thread_local_variables()->maybe_recycle_cell_)
+#define recycle_cc_count XOA (scheme_get_thread_local_variables()->recycle_cc_count_)
+#define main_init_error_buf XOA (scheme_get_thread_local_variables()->main_init_error_buf_)
+
+/* **************************************** */
+
+# define THREAD_LOCAL_DECL(x) /* empty */
+
+#endif
+
+/* **************************************** */
+
+#endif
diff --git a/src/mzscheme/mkincludes.ss b/src/mzscheme/mkincludes.ss
index 120568cca9..ccae8a5363 100644
--- a/src/mzscheme/mkincludes.ss
+++ b/src/mzscheme/mkincludes.ss
@@ -46,6 +46,7 @@
 (copy-if-newer mzsrcdir "include/scheme.h" #f
                (change-regexp "/[*]III[*]/"
                               "#define INCLUDE_WITHOUT_PATHS"))
+(copy-if-newer mzsrcdir "include/schthread.h")
 (copy-if-newer mzsrcdir "src/schemef.h")
 (copy-if-newer mzsrcdir "src/schvers.h")
 (copy-if-newer mzsrcdir "src/stypes.h")
diff --git a/src/mzscheme/src/Makefile.in b/src/mzscheme/src/Makefile.in
index 8f389c307b..b95cadcb60 100644
--- a/src/mzscheme/src/Makefile.in
+++ b/src/mzscheme/src/Makefile.in
@@ -240,39 +240,42 @@ SCONFIG =   $(srcdir)/../sconfig.h $(srcdir)/../uconfig.h
 
 # More dependencies
 
-salloc.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+COMMON_HEADERS = $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+                 $(srcdir)/../include/schthread.h 
+
+salloc.@LTO@: $(COMMON_HEADERS) \
             $(srcdir)/../gc/gc.h $(srcdir)/mzmark.c
-bignum.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+bignum.@LTO@: $(COMMON_HEADERS) \
           $(srcdir)/../src/stypes.h    
-bool.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+bool.@LTO@: $(COMMON_HEADERS) \
           $(srcdir)/../src/stypes.h $(srcdir)/mzeqchk.inc
-builtin.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h  \
+builtin.@LTO@: $(COMMON_HEADERS)  \
         $(srcdir)/../src/stypes.h  $(srcdir)/schminc.h $(srcdir)/startup.inc $(srcdir)/cstartup.inc
-char.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+char.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h  $(srcdir)/schuchar.inc
-complex.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h  \
+complex.@LTO@: $(COMMON_HEADERS)  \
          $(srcdir)/../src/stypes.h    
-dynext.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h  \
+dynext.@LTO@: $(COMMON_HEADERS)  \
          $(srcdir)/../src/stypes.h $(srcdir)/../src/schemex.h \
          $(srcdir)/schvers.h $(srcdir)/../gc/gc.h $(srcdir)/schemex.h
-env.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h  \
+env.@LTO@: $(COMMON_HEADERS)  \
         $(srcdir)/../src/stypes.h  $(srcdir)/schminc.h $(srcdir)/mzmark.c
-error.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+error.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h  
-eval.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+eval.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c \
           $(srcdir)/schmach.h $(srcdir)/mzstkchk.h $(srcdir)/schrunst.h \
 				$(srcdir)/future.h
-file.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+file.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c 
-fun.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+fun.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c $(srcdir)/schmap.inc \
 				$(srcdir)/future.h
 future.@LTO@: $(srcdir)/schpriv.h $(srcdir)/future.h $(SCONFIG) $(srcdir)/../include/scheme.h \
         $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c
-hash.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+hash.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c
-jit.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+jit.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h $(srcdir)/codetab.inc $(srcdir)/mzmark.c \
         $(srcdir)/lightning/i386/core.h $(srcdir)/lightning/i386/core-common.h \
         $(srcdir)/lightning/i386/asm.h $(srcdir)/lightning/i386/asm-common.h \
@@ -283,53 +286,53 @@ jit.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../includ
         $(srcdir)/lightning/ppc/funcs.h $(srcdir)/lightning/ppc/funcs-common.h \
         $(srcdir)/lightning/ppc/fp.h $(srcdir)/lightning/ppc/fp-common.h \
 				$(srcdir)/future.h
-list.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+list.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h  
-module.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+module.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h $(srcdir)/schfd.h $(srcdir)/mzmark.c
-network.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+network.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h  $(srcdir)/schfd.h $(srcdir)/mzmark.c
-numarith.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+numarith.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h $(srcdir)/nummacs.h
-number.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+number.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h $(srcdir)/nummacs.h
-numcomp.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+numcomp.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h $(srcdir)/nummacs.h
-numstr.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+numstr.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h  $(srcdir)/random.inc $(srcdir)/newrandom.inc
-places.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+places.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h  $(srcdir)/schfd.h $(srcdir)/mzmark.c
-port.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+port.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h  $(srcdir)/schfd.h $(srcdir)/mzmark.c
-portfun.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+portfun.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h $(srcdir)/schfd.h $(srcdir)/mzmark.c
-print.@LTO@: $(srcdir)/../include/scheme.h $(srcdir)/../src/stypes.h $(srcdir)/../src/schcpt.h \
-          $(srcdir)/schpriv.h $(srcdir)/schexn.h $(srcdir)/schvers.h $(SCONFIG) $(srcdir)/mzmark.c
-thread.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+print.@LTO@: $(COMMON_HEADERS) $(srcdir)/../src/stypes.h $(srcdir)/../src/schcpt.h \
+          $(srcdir)/schvers.h $(SCONFIG) $(srcdir)/mzmark.c
+thread.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h  $(srcdir)/schfd.h $(srcdir)/mzmark.c
-rational.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+rational.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h    
-read.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+read.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/schcpt.h $(srcdir)/schvers.h $(srcdir)/schminc.h \
         $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c
-regexp.@LTO@:  $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+regexp.@LTO@:  $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c $(srcdir)/schrx.h
-setjmpup.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+setjmpup.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h   $(srcdir)/schmach.h
-string.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+string.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h    $(srcdir)/schvers.h $(srcdir)/mzmark.c $(srcdir)/strops.inc \
          $(srcdir)/schustr.inc
-struct.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+struct.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c
-stxobj.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+stxobj.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h $(srcdir)/schfd.h $(srcdir)/mzmark.c
-symbol.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+symbol.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h   
-syntax.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+syntax.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c
-sema.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+sema.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c
-type.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+type.@LTO@: $(COMMON_HEADERS) \
         $(srcdir)/../src/stypes.h $(srcdir)/mzmark.c
-vector.@LTO@: $(srcdir)/schpriv.h $(srcdir)/schexn.h $(SCONFIG) $(srcdir)/../include/scheme.h \
+vector.@LTO@: $(COMMON_HEADERS) \
          $(srcdir)/../src/stypes.h
diff --git a/src/mzscheme/src/bignum.c b/src/mzscheme/src/bignum.c
index 8e418954cf..be985853a6 100644
--- a/src/mzscheme/src/bignum.c
+++ b/src/mzscheme/src/bignum.c
@@ -111,9 +111,8 @@ static Scheme_Object *bignum_one;
 
 extern void GC_check(void *p);
 
-#define BIGNUM_CACHE_SIZE 16
-static THREAD_LOCAL void *bignum_cache[BIGNUM_CACHE_SIZE];
-static THREAD_LOCAL int cache_count;
+THREAD_LOCAL_DECL(static void *bignum_cache[BIGNUM_CACHE_SIZE]);
+THREAD_LOCAL_DECL(static int cache_count);
 
 static void *copy_to_protected(void *p, long len, int zero)
 {
diff --git a/src/mzscheme/src/codetab.inc b/src/mzscheme/src/codetab.inc
index 06a5f544c2..d79b04fa79 100644
--- a/src/mzscheme/src/codetab.inc
+++ b/src/mzscheme/src/codetab.inc
@@ -20,15 +20,15 @@ extern MZ_DLLIMPORT int GC_is_marked(void *);
 #define NODE_STARTS_OFFSET 1
 #define NODE_GCABLE_OFFSET 2
 
-static THREAD_LOCAL void **tree;
-static THREAD_LOCAL int during_set;
+THREAD_LOCAL_DECL(static void **codetab_tree);
+THREAD_LOCAL_DECL(static int during_set);
 
 static int do_clear_symbols(void **t, unsigned long start, int offset, unsigned long addr, int clearing);
 
 static void *find_symbol(unsigned long v)
 {
   unsigned long k;
-  void **t = tree, *val;
+  void **t = codetab_tree, *val;
   int offset = (JIT_WORD_SIZE * 8);
   
   while (offset) {
@@ -68,14 +68,14 @@ static void add_symbol(unsigned long start, unsigned long end, void *value, int
   int offset = (JIT_WORD_SIZE * 8), split_offset = 0;
   void **t1, **t2, **split_t, *val1, *val2;
 
-  if (!tree) {
-    REGISTER_SO(tree);
-    tree = malloc_node();
+  if (!codetab_tree) {
+    REGISTER_SO(codetab_tree);
+    codetab_tree = malloc_node();
   }
 
   during_set++;
   
-  t1 = t2 = tree;
+  t1 = t2 = codetab_tree;
   split_t = NULL;
   while (offset) {
     offset -= LOG_KEY_SIZE;
@@ -175,7 +175,7 @@ static void add_symbol(unsigned long start, unsigned long end, void *value, int
     /* Prune empty branches in the tree. Only do this if this
        object is mapped deeply enough in the tree, otherwise
        we end up scanning the whole tree. */
-    do_clear_symbols(tree, start, 0, 0, 0);
+    do_clear_symbols(codetab_tree, start, 0, 0, 0);
   }
 #endif
 }
@@ -258,8 +258,8 @@ static int do_clear_symbols(void **t, unsigned long start, int offset, unsigned
 
 static void clear_symbols_for_collected()
 {
-  if (tree) {
-    do_clear_symbols(tree, 0, (JIT_WORD_SIZE * 8) - LOG_KEY_SIZE, 0, 0); 
+  if (codetab_tree) {
+    do_clear_symbols(codetab_tree, 0, (JIT_WORD_SIZE * 8) - LOG_KEY_SIZE, 0, 0); 
   }
 }
 
diff --git a/src/mzscheme/src/cstartup.inc b/src/mzscheme/src/cstartup.inc
index e675158c0c..51a29c08c7 100644
--- a/src/mzscheme/src/cstartup.inc
+++ b/src/mzscheme/src/cstartup.inc
@@ -1,43 +1,43 @@
   {
-    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,7,52,46,50,46,50,46,53,50,0,0,0,1,0,0,3,0,12,0,
-17,0,21,0,26,0,31,0,35,0,42,0,45,0,58,0,65,0,72,0,78,
+    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,7,52,46,50,46,51,46,50,50,0,0,0,1,0,0,3,0,12,0,
+17,0,20,0,27,0,40,0,47,0,51,0,58,0,63,0,68,0,72,0,78,
 0,92,0,106,0,109,0,115,0,119,0,121,0,132,0,134,0,148,0,155,0,
 177,0,179,0,193,0,4,1,33,1,44,1,55,1,65,1,101,1,134,1,167,
 1,226,1,36,2,114,2,180,2,185,2,205,2,96,3,116,3,167,3,233,3,
 118,4,4,5,56,5,79,5,158,5,0,0,105,7,0,0,29,11,11,68,104,
-101,114,101,45,115,116,120,64,108,101,116,42,63,108,101,116,64,119,104,101,110,
-64,99,111,110,100,63,97,110,100,66,108,101,116,114,101,99,62,111,114,72,112,
-97,114,97,109,101,116,101,114,105,122,101,66,100,101,102,105,110,101,66,117,110,
-108,101,115,115,65,113,117,111,116,101,29,94,2,13,68,35,37,107,101,114,110,
+101,114,101,45,115,116,120,64,99,111,110,100,62,111,114,66,108,101,116,114,101,
+99,72,112,97,114,97,109,101,116,101,114,105,122,101,66,117,110,108,101,115,115,
+63,108,101,116,66,100,101,102,105,110,101,64,119,104,101,110,64,108,101,116,42,
+63,97,110,100,65,113,117,111,116,101,29,94,2,13,68,35,37,107,101,114,110,
 101,108,11,29,94,2,13,68,35,37,112,97,114,97,109,122,11,62,105,102,65,
 98,101,103,105,110,63,115,116,120,61,115,70,108,101,116,45,118,97,108,117,101,
 115,61,120,73,108,101,116,114,101,99,45,118,97,108,117,101,115,66,108,97,109,
 98,100,97,1,20,112,97,114,97,109,101,116,101,114,105,122,97,116,105,111,110,
 45,107,101,121,61,118,73,100,101,102,105,110,101,45,118,97,108,117,101,115,97,
-35,11,8,240,70,69,0,0,95,159,2,15,35,35,159,2,14,35,35,159,2,
-14,35,35,16,20,2,9,2,1,2,3,2,1,2,4,2,1,2,5,2,1,
-2,6,2,1,2,7,2,1,2,8,2,1,2,10,2,1,2,11,2,1,2,
-12,2,1,97,36,11,8,240,70,69,0,0,93,159,2,14,35,36,16,2,2,
-2,161,2,1,36,2,2,2,1,2,2,96,11,11,8,240,70,69,0,0,16,
-0,96,37,11,8,240,70,69,0,0,16,0,13,16,4,35,29,11,11,2,1,
+35,11,8,240,168,70,0,0,95,159,2,15,35,35,159,2,14,35,35,159,2,
+14,35,35,16,20,2,3,2,1,2,5,2,1,2,6,2,1,2,7,2,1,
+2,8,2,1,2,9,2,1,2,10,2,1,2,4,2,1,2,11,2,1,2,
+12,2,1,97,36,11,8,240,168,70,0,0,93,159,2,14,35,36,16,2,2,
+2,161,2,1,36,2,2,2,1,2,2,96,11,11,8,240,168,70,0,0,16,
+0,96,37,11,8,240,168,70,0,0,16,0,13,16,4,35,29,11,11,2,1,
 11,18,16,2,99,64,104,101,114,101,8,31,8,30,8,29,8,28,8,27,93,
-8,224,77,69,0,0,95,9,8,224,77,69,0,0,2,1,27,248,22,137,4,
+8,224,175,70,0,0,95,9,8,224,175,70,0,0,2,1,27,248,22,137,4,
 195,249,22,130,4,80,158,38,35,251,22,77,2,16,248,22,92,199,12,249,22,
 67,2,17,248,22,94,201,27,248,22,137,4,195,249,22,130,4,80,158,38,35,
 251,22,77,2,16,248,22,92,199,249,22,67,2,17,248,22,94,201,12,27,248,
 22,69,248,22,137,4,196,28,248,22,75,193,20,15,159,36,35,36,28,248,22,
 75,248,22,69,194,248,22,68,193,249,22,130,4,80,158,38,35,251,22,77,2,
-16,248,22,68,199,249,22,67,2,7,248,22,69,201,11,18,16,2,101,10,8,
+16,248,22,68,199,249,22,67,2,12,248,22,69,201,11,18,16,2,101,10,8,
 31,8,30,8,29,8,28,8,27,16,4,11,11,2,18,3,1,8,101,110,118,
-49,49,48,51,49,16,4,11,11,2,19,3,1,8,101,110,118,49,49,48,51,
-50,93,8,224,78,69,0,0,95,9,8,224,78,69,0,0,2,1,27,248,22,
+49,49,51,56,56,16,4,11,11,2,19,3,1,8,101,110,118,49,49,51,56,
+57,93,8,224,176,70,0,0,95,9,8,224,176,70,0,0,2,1,27,248,22,
 69,248,22,137,4,196,28,248,22,75,193,20,15,159,36,35,36,28,248,22,75,
 248,22,69,194,248,22,68,193,249,22,130,4,80,158,38,35,250,22,77,2,20,
 248,22,77,249,22,77,248,22,77,2,21,248,22,68,201,251,22,77,2,16,2,
-21,2,21,249,22,67,2,9,248,22,69,204,18,16,2,101,11,8,31,8,30,
-8,29,8,28,8,27,16,4,11,11,2,18,3,1,8,101,110,118,49,49,48,
-51,52,16,4,11,11,2,19,3,1,8,101,110,118,49,49,48,51,53,93,8,
-224,79,69,0,0,95,9,8,224,79,69,0,0,2,1,248,22,137,4,193,27,
+21,2,21,249,22,67,2,4,248,22,69,204,18,16,2,101,11,8,31,8,30,
+8,29,8,28,8,27,16,4,11,11,2,18,3,1,8,101,110,118,49,49,51,
+57,49,16,4,11,11,2,19,3,1,8,101,110,118,49,49,51,57,50,93,8,
+224,177,70,0,0,95,9,8,224,177,70,0,0,2,1,248,22,137,4,193,27,
 248,22,137,4,194,249,22,67,248,22,77,248,22,68,196,248,22,69,195,27,248,
 22,69,248,22,137,4,23,197,1,249,22,130,4,80,158,38,35,28,248,22,53,
 248,22,131,4,248,22,68,23,198,2,27,249,22,2,32,0,89,162,8,44,36,
@@ -51,8 +51,8 @@
 249,22,2,32,0,89,162,8,44,36,46,9,222,33,42,248,22,137,4,248,22,
 68,201,248,22,69,198,27,248,22,69,248,22,137,4,196,27,248,22,137,4,248,
 22,68,195,249,22,130,4,80,158,39,35,28,248,22,75,195,250,22,78,2,20,
-9,248,22,69,199,250,22,77,2,4,248,22,77,248,22,68,199,250,22,78,2,
-3,248,22,69,201,248,22,69,202,27,248,22,69,248,22,137,4,23,197,1,27,
+9,248,22,69,199,250,22,77,2,8,248,22,77,248,22,68,199,250,22,78,2,
+11,248,22,69,201,248,22,69,202,27,248,22,69,248,22,137,4,23,197,1,27,
 249,22,1,22,81,249,22,2,22,137,4,248,22,137,4,248,22,68,199,249,22,
 130,4,80,158,39,35,251,22,77,1,22,119,105,116,104,45,99,111,110,116,105,
 110,117,97,116,105,111,110,45,109,97,114,107,2,24,250,22,78,1,23,101,120,
@@ -62,14 +62,14 @@
 22,69,203,27,248,22,69,248,22,137,4,196,28,248,22,75,193,20,15,159,36,
 35,36,249,22,130,4,80,158,38,35,27,248,22,137,4,248,22,68,197,28,249,
 22,167,8,62,61,62,248,22,131,4,248,22,92,196,250,22,77,2,20,248,22,
-77,249,22,77,21,93,2,25,248,22,68,199,250,22,78,2,6,249,22,77,2,
+77,249,22,77,21,93,2,25,248,22,68,199,250,22,78,2,3,249,22,77,2,
 25,249,22,77,248,22,101,203,2,25,248,22,69,202,251,22,77,2,16,28,249,
 22,167,8,248,22,131,4,248,22,68,200,64,101,108,115,101,10,248,22,68,197,
-250,22,78,2,20,9,248,22,69,200,249,22,67,2,6,248,22,69,202,100,8,
+250,22,78,2,20,9,248,22,69,200,249,22,67,2,3,248,22,69,202,100,8,
 31,8,30,8,29,8,28,8,27,16,4,11,11,2,18,3,1,8,101,110,118,
-49,49,48,53,55,16,4,11,11,2,19,3,1,8,101,110,118,49,49,48,53,
-56,93,8,224,80,69,0,0,18,16,2,158,94,10,64,118,111,105,100,8,47,
-95,9,8,224,80,69,0,0,2,1,27,248,22,69,248,22,137,4,196,249,22,
+49,49,52,49,52,16,4,11,11,2,19,3,1,8,101,110,118,49,49,52,49,
+53,93,8,224,178,70,0,0,18,16,2,158,94,10,64,118,111,105,100,8,47,
+95,9,8,224,178,70,0,0,2,1,27,248,22,69,248,22,137,4,196,249,22,
 130,4,80,158,38,35,28,248,22,53,248,22,131,4,248,22,68,197,250,22,77,
 2,26,248,22,77,248,22,68,199,248,22,92,198,27,248,22,131,4,248,22,68,
 197,250,22,77,2,26,248,22,77,248,22,68,197,250,22,78,2,23,248,22,69,
@@ -81,25 +81,25 @@
 2,3,2,4,2,5,2,6,2,7,2,8,2,9,2,10,2,11,2,12,35,
 45,36,11,11,11,16,0,16,0,16,0,35,35,11,11,11,11,16,0,16,0,
 16,0,35,35,16,11,16,5,2,2,20,15,159,35,35,35,35,20,102,159,35,
-16,0,16,1,33,32,10,16,5,2,12,89,162,8,44,36,52,9,223,0,33,
-33,35,20,102,159,35,16,1,2,2,16,0,11,16,5,2,5,89,162,8,44,
+16,0,16,1,33,32,10,16,5,2,7,89,162,8,44,36,52,9,223,0,33,
+33,35,20,102,159,35,16,1,2,2,16,0,11,16,5,2,10,89,162,8,44,
 36,52,9,223,0,33,34,35,20,102,159,35,16,1,2,2,16,0,11,16,5,
-2,7,89,162,8,44,36,52,9,223,0,33,35,35,20,102,159,35,16,1,2,
-2,16,1,33,36,11,16,5,2,9,89,162,8,44,36,55,9,223,0,33,37,
-35,20,102,159,35,16,1,2,2,16,1,33,38,11,16,5,2,4,89,162,8,
+2,12,89,162,8,44,36,52,9,223,0,33,35,35,20,102,159,35,16,1,2,
+2,16,1,33,36,11,16,5,2,4,89,162,8,44,36,55,9,223,0,33,37,
+35,20,102,159,35,16,1,2,2,16,1,33,38,11,16,5,2,8,89,162,8,
 44,36,57,9,223,0,33,41,35,20,102,159,35,16,1,2,2,16,0,11,16,
-5,2,8,89,162,8,44,36,52,9,223,0,33,43,35,20,102,159,35,16,1,
-2,2,16,0,11,16,5,2,3,89,162,8,44,36,53,9,223,0,33,44,35,
-20,102,159,35,16,1,2,2,16,0,11,16,5,2,10,89,162,8,44,36,54,
-9,223,0,33,45,35,20,102,159,35,16,1,2,2,16,0,11,16,5,2,6,
+5,2,5,89,162,8,44,36,52,9,223,0,33,43,35,20,102,159,35,16,1,
+2,2,16,0,11,16,5,2,11,89,162,8,44,36,53,9,223,0,33,44,35,
+20,102,159,35,16,1,2,2,16,0,11,16,5,2,6,89,162,8,44,36,54,
+9,223,0,33,45,35,20,102,159,35,16,1,2,2,16,0,11,16,5,2,3,
 89,162,8,44,36,57,9,223,0,33,46,35,20,102,159,35,16,1,2,2,16,
-1,33,48,11,16,5,2,11,89,162,8,44,36,53,9,223,0,33,49,35,20,
+1,33,48,11,16,5,2,9,89,162,8,44,36,53,9,223,0,33,49,35,20,
 102,159,35,16,1,2,2,16,0,11,16,0,94,2,14,2,15,93,2,14,9,
 9,35,0};
     EVAL_ONE_SIZED_STR((char *)expr, 2018);
   }
   {
-    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,7,52,46,50,46,50,46,53,59,0,0,0,1,0,0,13,0,18,0,
+    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,7,52,46,50,46,51,46,50,59,0,0,0,1,0,0,13,0,18,0,
 35,0,50,0,68,0,84,0,94,0,112,0,132,0,148,0,166,0,197,0,226,
 0,248,0,6,1,12,1,26,1,31,1,41,1,49,1,77,1,109,1,154,1,
 199,1,223,1,6,2,8,2,65,2,155,3,196,3,31,5,135,5,239,5,100,
@@ -341,26 +341,26 @@
     EVAL_ONE_SIZED_STR((char *)expr, 5006);
   }
   {
-    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,7,52,46,50,46,50,46,53,8,0,0,0,1,0,0,6,0,19,0,
-34,0,48,0,62,0,76,0,118,0,0,0,23,1,0,0,65,113,117,111,116,
+    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,7,52,46,50,46,51,46,50,8,0,0,0,1,0,0,6,0,19,0,
+34,0,48,0,62,0,76,0,118,0,0,0,38,1,0,0,65,113,117,111,116,
 101,29,94,2,1,67,35,37,117,116,105,108,115,11,29,94,2,1,69,35,37,
 110,101,116,119,111,114,107,11,29,94,2,1,68,35,37,112,97,114,97,109,122,
 11,29,94,2,1,68,35,37,101,120,112,111,98,115,11,29,94,2,1,68,35,
-37,107,101,114,110,101,108,11,97,35,11,8,240,204,69,0,0,98,159,2,2,
+37,107,101,114,110,101,108,11,97,35,11,8,240,46,71,0,0,98,159,2,2,
 35,35,159,2,3,35,35,159,2,4,35,35,159,2,5,35,35,159,2,6,35,
 35,159,2,6,35,35,16,0,159,35,20,102,159,35,16,1,11,16,0,83,158,
 41,20,100,144,69,35,37,98,117,105,108,116,105,110,29,11,11,11,11,11,18,
 96,11,42,42,42,35,80,158,35,35,20,102,159,35,16,0,16,0,16,0,35,
 16,0,35,16,0,35,11,11,38,35,11,11,11,16,0,16,0,16,0,35,35,
 36,11,11,11,16,0,16,0,16,0,35,35,11,11,11,11,16,0,16,0,16,
-0,35,35,16,0,16,0,100,2,6,2,5,29,94,2,1,69,35,37,102,111,
+0,35,35,16,0,16,0,101,2,6,2,5,29,94,2,1,69,35,37,102,111,
 114,101,105,103,110,11,29,94,2,1,68,35,37,117,110,115,97,102,101,11,2,
-4,2,3,2,2,29,94,2,1,67,35,37,112,108,97,99,101,11,9,9,9,
-35,0};
-    EVAL_ONE_SIZED_STR((char *)expr, 316);
+4,2,3,2,2,29,94,2,1,67,35,37,112,108,97,99,101,11,29,94,2,
+1,69,35,37,102,117,116,117,114,101,115,11,9,9,9,35,0};
+    EVAL_ONE_SIZED_STR((char *)expr, 331);
   }
   {
-    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,7,52,46,50,46,50,46,53,56,0,0,0,1,0,0,11,0,38,0,
+    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,7,52,46,50,46,51,46,50,56,0,0,0,1,0,0,11,0,38,0,
 44,0,57,0,66,0,73,0,95,0,117,0,143,0,155,0,173,0,193,0,205,
 0,221,0,244,0,0,1,31,1,38,1,43,1,48,1,53,1,58,1,67,1,
 72,1,76,1,84,1,93,1,101,1,204,1,249,1,13,2,42,2,73,2,129,
diff --git a/src/mzscheme/src/env.c b/src/mzscheme/src/env.c
index a25a491421..a4c4d2ac19 100644
--- a/src/mzscheme/src/env.c
+++ b/src/mzscheme/src/env.c
@@ -67,10 +67,9 @@ static Scheme_Object *scheme_local[MAX_CONST_LOCAL_POS][MAX_CONST_LOCAL_TYPES][M
 #define SCHEME_TOPLEVEL_FLAGS_MASK 0x3
 static Scheme_Object *toplevels[MAX_CONST_TOPLEVEL_DEPTH][MAX_CONST_TOPLEVEL_POS][SCHEME_TOPLEVEL_FLAGS_MASK + 1];
 
-/* globals THREAD_LOCAL 
- * if locked theses are probably sharable*/
-static THREAD_LOCAL Scheme_Hash_Table *toplevels_ht;
-static THREAD_LOCAL Scheme_Hash_Table *locals_ht[2];
+/* If locked, these are probably sharable: */
+THREAD_LOCAL_DECL(static Scheme_Hash_Table *toplevels_ht);
+THREAD_LOCAL_DECL(static Scheme_Hash_Table *locals_ht[2]);
 
 /* local functions */
 static void make_kernel_env(void);
@@ -468,9 +467,7 @@ static Scheme_Env *place_instance_init_post_kernel() {
 #if defined(MZ_USE_PLACES)
   scheme_jit_fill_threadlocal_table();
 #endif
-#ifdef FUTURES_ENABLED 
   scheme_init_futures(env);
-#endif
 
 #ifndef DONT_USE_FOREIGN
   scheme_init_foreign(env);
@@ -502,8 +499,8 @@ Scheme_Env *scheme_place_instance_init(void *stack_base) {
 }
 
 void scheme_place_instance_destroy() {
-#if defined(USE_PTHREAD_THREAD_TIMER) && defined(MZ_USE_PLACES)
-  kill_green_thread_timer();
+#if defined(MZ_USE_PLACES)
+  scheme_kill_green_thread_timer();
 #endif
 }
 
diff --git a/src/mzscheme/src/eval.c b/src/mzscheme/src/eval.c
index daabff018b..48cad1e506 100644
--- a/src/mzscheme/src/eval.c
+++ b/src/mzscheme/src/eval.c
@@ -149,23 +149,23 @@
 #define EMBEDDED_DEFINES_START_ANYWHERE 0
 
 /* globals */
-THREAD_LOCAL volatile int scheme_fuel_counter;
+THREAD_LOCAL_DECL(volatile int scheme_fuel_counter);
 
 int scheme_startup_use_jit = 1;
 void scheme_set_startup_use_jit(int v) { scheme_startup_use_jit =  v; }
 
 /* THREAD LOCAL SHARED */
 #ifdef USE_STACK_BOUNDARY_VAR
-THREAD_LOCAL unsigned long scheme_stack_boundary;
-THREAD_LOCAL unsigned long volatile scheme_jit_stack_boundary;
+THREAD_LOCAL_DECL(unsigned long scheme_stack_boundary);
+THREAD_LOCAL_DECL(unsigned long volatile scheme_jit_stack_boundary);
 #endif
-static THREAD_LOCAL Scheme_Object *quick_stx;
+THREAD_LOCAL_DECL(static Scheme_Object *quick_stx);
 
 /* global counters */
 /* FIXME needs to be atomically incremented */
 int scheme_overflow_count;
 int get_overflow_count() { return scheme_overflow_count; }
-int THREAD_LOCAL scheme_continuation_application_count;
+THREAD_LOCAL_DECL(int scheme_continuation_application_count);
 
 /* read-only globals */
 Scheme_Object *scheme_eval_waiting;
@@ -8795,18 +8795,18 @@ scheme_do_eval(Scheme_Object *obj, int num_rands, Scheme_Object **rands,
 	{
 	  GC_CAN_IGNORE Scheme_Quote_Syntax *qs = (Scheme_Quote_Syntax *)obj;
 	  Scheme_Object **globs;
-	  int i, c, p;
+	  int i, c, pos;
 
 	  i = qs->position;
 	  c = qs->depth;
-	  p = qs->midpoint;
+	  pos = qs->midpoint;
 
 	  globs = (Scheme_Object **)RUNSTACK[c];
-	  v = globs[i+p+1];
+	  v = globs[i+pos+1];
 	  if (!v) {
-	    v = globs[p];
+	    v = globs[pos];
 	    v = scheme_delayed_rename((Scheme_Object **)v, i);
-	    globs[i+p+1] = v;
+	    globs[i+pos+1] = v;
 	  }
 
 	  goto returnv_never_multi;
diff --git a/src/mzscheme/src/fun.c b/src/mzscheme/src/fun.c
index 6631532145..bf32589335 100644
--- a/src/mzscheme/src/fun.c
+++ b/src/mzscheme/src/fun.c
@@ -89,8 +89,8 @@ Scheme_Object *scheme_tail_call_waiting;
 Scheme_Object *scheme_inferred_name_symbol;
 Scheme_Object *scheme_default_prompt_tag;
 
-THREAD_LOCAL int scheme_cont_capture_count;
-static THREAD_LOCAL int scheme_prompt_capture_count;
+THREAD_LOCAL_DECL(int scheme_cont_capture_count);
+THREAD_LOCAL_DECL(static int scheme_prompt_capture_count);
 
 
 /* locals */
@@ -169,18 +169,18 @@ static Scheme_Object *abort_continuation_proc;
 
 static Scheme_Object *internal_call_cc_prim;
 
-/* CACHES NEED TO BE THREAD LOCAL */
-static THREAD_LOCAL Scheme_Prompt *available_prompt;
-static THREAD_LOCAL Scheme_Prompt *available_cws_prompt;
-static THREAD_LOCAL Scheme_Prompt *available_regular_prompt;
-static THREAD_LOCAL Scheme_Dynamic_Wind *available_prompt_dw;
-static THREAD_LOCAL Scheme_Meta_Continuation *available_prompt_mc;
-static THREAD_LOCAL Scheme_Object *cached_beg_stx;
-static THREAD_LOCAL Scheme_Object *cached_dv_stx;
-static THREAD_LOCAL Scheme_Object *cached_ds_stx;
-static THREAD_LOCAL int cached_stx_phase;
-static THREAD_LOCAL Scheme_Cont *offstack_cont;
-static THREAD_LOCAL Scheme_Overflow *offstack_overflow;
+/* Caches need to be thread-local: */
+THREAD_LOCAL_DECL(static Scheme_Prompt *available_prompt);
+THREAD_LOCAL_DECL(static Scheme_Prompt *available_cws_prompt);
+THREAD_LOCAL_DECL(static Scheme_Prompt *available_regular_prompt);
+THREAD_LOCAL_DECL(static Scheme_Dynamic_Wind *available_prompt_dw);
+THREAD_LOCAL_DECL(static Scheme_Meta_Continuation *available_prompt_mc);
+THREAD_LOCAL_DECL(static Scheme_Object *cached_beg_stx);
+THREAD_LOCAL_DECL(static Scheme_Object *cached_dv_stx);
+THREAD_LOCAL_DECL(static Scheme_Object *cached_ds_stx);
+THREAD_LOCAL_DECL(static int cached_stx_phase);
+THREAD_LOCAL_DECL(static Scheme_Cont *offstack_cont);
+THREAD_LOCAL_DECL(static Scheme_Overflow *offstack_overflow);
 
 
 typedef void (*DW_PrePost_Proc)(void *);
@@ -1833,8 +1833,8 @@ static void initialize_prompt(Scheme_Thread *p, Scheme_Prompt *prompt, void *sta
 
 typedef Scheme_Object *(*Overflow_K_Proc)(void);
 
-THREAD_LOCAL Scheme_Overflow_Jmp *scheme_overflow_jmp;
-THREAD_LOCAL void *scheme_overflow_stack_start;
+THREAD_LOCAL_DECL(Scheme_Overflow_Jmp *scheme_overflow_jmp);
+THREAD_LOCAL_DECL(void *scheme_overflow_stack_start);
 
 MZ_DO_NOT_INLINE(void scheme_really_create_overflow(void *stack_base));
 
diff --git a/src/mzscheme/src/future.c b/src/mzscheme/src/future.c
index e98a54007d..bf35938714 100644
--- a/src/mzscheme/src/future.c
+++ b/src/mzscheme/src/future.c
@@ -7,7 +7,39 @@
 int g_print_prims = 0;
 #endif
 
-#ifdef FUTURES_ENABLED
+#ifndef FUTURES_ENABLED
+
+/* Futures not enabled, but make a stub module */
+
+static Scheme_Object *future(int argc, Scheme_Object *argv[])
+{
+  scheme_signal_error("future: not enabled");
+  return NULL;
+}
+
+static Scheme_Object *touch(int argc, Scheme_Object *argv[])
+{
+  scheme_signal_error("touch: not enabled");
+  return NULL;
+}
+
+# define FUTURE_PRIM_W_ARITY(name, func, a1, a2, env) GLOBAL_PRIM_W_ARITY(name, func, a1, a2, env)
+
+void scheme_init_futures(Scheme_Env *env)
+{
+  Scheme_Env *newenv;
+  
+  newenv = scheme_primitive_module(scheme_intern_symbol("#%futures"), 
+                                   env);
+
+  FUTURE_PRIM_W_ARITY("future",      future,       1, 1, newenv);
+  FUTURE_PRIM_W_ARITY("touch",       touch,        1, 1, newenv);
+
+  scheme_finish_primitive_module(newenv);
+  scheme_protect_primitive_provide(newenv, NULL);
+}
+
+#else
 
 #include "future.h"
 #include <stdlib.h>
@@ -38,7 +70,7 @@ static pthread_mutex_t gc_ok_m = PTHREAD_MUTEX_INITIALIZER;
 static pthread_cond_t gc_ok_c = PTHREAD_COND_INITIALIZER;
 static int gc_not_ok;
 #ifdef MZ_PRECISE_GC
-extern THREAD_LOCAL unsigned long GC_gen0_alloc_page_ptr;
+THREAD_LOCAL_DECL(extern unsigned long GC_gen0_alloc_page_ptr);
 #endif
 
 future_t **g_current_ft;
@@ -51,7 +83,7 @@ extern void scheme_on_demand_generate_lambda(Scheme_Native_Closure *nc, int argc
 static void start_gc_not_ok();
 static void end_gc_not_ok();
 
-static THREAD_LOCAL future_t *current_ft;
+THREAD_LOCAL_DECL(static future_t *current_ft);
 
 //Stuff for scheme runstack 
 //Some of these may mimic defines in thread.c, but are redefined here 
@@ -606,6 +638,8 @@ void *worker_thread_future_loop(void *arg)
         future_t *ft;
         int id = *(int *)arg;
 
+        scheme_init_os_thread();
+
 	//Set processor affinity
 	/*pthread_mutex_lock(&g_future_queue_mutex);
 	if (pthread_setaffinity_np(pthread_self(), sizeof(g_cur_cpu_mask), &g_cur_cpu_mask))
diff --git a/src/mzscheme/src/future.h b/src/mzscheme/src/future.h
index 799c2dd275..7af7e16fce 100644
--- a/src/mzscheme/src/future.h
+++ b/src/mzscheme/src/future.h
@@ -29,7 +29,6 @@ extern Scheme_Object *end_primitive_tracking(int argc, Scheme_Object *argv[]);
 extern Scheme_Object *future(int argc, Scheme_Object *argv[]);
 extern Scheme_Object *touch(int argc, Scheme_Object *argv[]);
 extern Scheme_Object *num_processors(int argc, Scheme_Object *argv[]);
-extern void scheme_init_futures(Scheme_Env *env);
 extern int future_do_runtimecall(void *func, int sigtype, void *args, void *retval);
 extern void futures_init(void);
 
diff --git a/src/mzscheme/src/jit.c b/src/mzscheme/src/jit.c
index 25ded8c074..8812cdcfcb 100644
--- a/src/mzscheme/src/jit.c
+++ b/src/mzscheme/src/jit.c
@@ -288,9 +288,8 @@ void scheme_jit_fill_threadlocal_table();
 # define tl_save_fp                        11
 # define tl_scheme_fuel_counter            12
 # define tl_scheme_jit_stack_boundary      13
-# define NUM_tl_VARS                       14
 
-static THREAD_LOCAL void *thread_local_pointers[NUM_tl_VARS];
+THREAD_LOCAL_DECL(static void *thread_local_pointers[NUM_tl_VARS]);
 
 #ifdef MZ_XFORM
 START_XFORM_SKIP;
@@ -352,17 +351,11 @@ typedef struct {
   Scheme_Native_Closure_Data *case_lam;
 } Scheme_Native_Closure_Data_Plus_Case;
 
-/* This structure must be 4 words: */
-typedef struct {
-  void *orig_return_address;
-  void *stack_frame;
-  Scheme_Object *cache;
-  void *orig_result;
-} Stack_Cache_Elem;
+/* The Stack_Cache_Elem structure type (define in schthread.h)
+   must have a size of  4 words. */
 
-#define STACK_CACHE_SIZE 32
-static THREAD_LOCAL Stack_Cache_Elem stack_cache_stack[STACK_CACHE_SIZE];
-static THREAD_LOCAL long stack_cache_stack_pos = 0;
+THREAD_LOCAL_DECL(static Stack_Cache_Elem stack_cache_stack[STACK_CACHE_SIZE]);
+THREAD_LOCAL_DECL(static long stack_cache_stack_pos = 0);
 
 static void *decrement_cache_stack_pos(void *p)
 {
@@ -377,8 +370,8 @@ static void *decrement_cache_stack_pos(void *p)
 
 #include "codetab.inc"
 
-static THREAD_LOCAL Scheme_Object **fixup_runstack_base;
-static THREAD_LOCAL int fixup_already_in_place;
+THREAD_LOCAL_DECL(static Scheme_Object **fixup_runstack_base);
+THREAD_LOCAL_DECL(static int fixup_already_in_place);
 
 static Scheme_Object *_scheme_tail_apply_from_native_fixup_args(Scheme_Object *rator,
                                                                 int argc,
@@ -1365,7 +1358,7 @@ static void _jit_prolog_again(mz_jit_state *jitter, int n, int ret_addr_reg)
 #endif
 
 #ifdef CAN_INLINE_ALLOC
-extern THREAD_LOCAL unsigned long GC_gen0_alloc_page_ptr;
+THREAD_LOCAL_DECL(extern unsigned long GC_gen0_alloc_page_ptr);
 long GC_initial_word(int sizeb);
 void GC_initial_words(char *buffer, int sizeb);
 long GC_compute_alloc_size(long sizeb);
@@ -1375,12 +1368,12 @@ static void *retry_alloc_code;
 static void *retry_alloc_code_keep_r0_r1;
 static void *retry_alloc_code_keep_fpr1;
 
-static THREAD_LOCAL void *retry_alloc_r1; /* set by prepare_retry_alloc() */
+THREAD_LOCAL_DECL(static void *retry_alloc_r1); /* set by prepare_retry_alloc() */
 
 static int generate_alloc_retry(mz_jit_state *jitter, int i);
 
 #ifdef JIT_USE_FP_OPS
-static THREAD_LOCAL double save_fp;
+THREAD_LOCAL_DECL(static double save_fp);
 #endif
 
 static void *prepare_retry_alloc(void *p, void *p2)
diff --git a/src/mzscheme/src/module.c b/src/mzscheme/src/module.c
index 232223b99a..daff64468b 100644
--- a/src/mzscheme/src/module.c
+++ b/src/mzscheme/src/module.c
@@ -198,11 +198,11 @@ static Scheme_Bucket_Table *initial_toplevel;
 static Scheme_Object *empty_self_modidx;
 static Scheme_Object *empty_self_modname;
 
-static THREAD_LOCAL Scheme_Bucket_Table *starts_table;
+THREAD_LOCAL_DECL(static Scheme_Bucket_Table *starts_table);
 
 /* caches */
-static THREAD_LOCAL Scheme_Modidx *modidx_caching_chain;
-static THREAD_LOCAL Scheme_Object *global_shift_cache;
+THREAD_LOCAL_DECL(static Scheme_Modidx *modidx_caching_chain);
+THREAD_LOCAL_DECL(static Scheme_Object *global_shift_cache);
 #define GLOBAL_SHIFT_CACHE_SIZE 40
 #ifdef USE_SENORA_GC
 # define SHIFT_CACHE_NULL scheme_false
diff --git a/src/mzscheme/src/places.c b/src/mzscheme/src/places.c
index ae56bd1561..49abf639f8 100644
--- a/src/mzscheme/src/places.c
+++ b/src/mzscheme/src/places.c
@@ -9,7 +9,7 @@
 
 
 mz_proc_thread *scheme_master_proc_thread;
-THREAD_LOCAL mz_proc_thread *proc_thread_self;
+THREAD_LOCAL_DECL(mz_proc_thread *proc_thread_self);
 
 Scheme_Object *scheme_place(int argc, Scheme_Object *args[]);
 static Scheme_Object *scheme_place_wait(int argc, Scheme_Object *args[]);
diff --git a/src/mzscheme/src/port.c b/src/mzscheme/src/port.c
index e10f7176da..35bfb7f79e 100644
--- a/src/mzscheme/src/port.c
+++ b/src/mzscheme/src/port.c
@@ -303,11 +303,11 @@ typedef struct Scheme_FD {
 
 /* globals */
 Scheme_Object scheme_eof[1];
-THREAD_LOCAL Scheme_Object *scheme_orig_stdout_port;
-THREAD_LOCAL Scheme_Object *scheme_orig_stderr_port;
-THREAD_LOCAL Scheme_Object *scheme_orig_stdin_port;
+THREAD_LOCAL_DECL(Scheme_Object *scheme_orig_stdout_port);
+THREAD_LOCAL_DECL(Scheme_Object *scheme_orig_stderr_port);
+THREAD_LOCAL_DECL(Scheme_Object *scheme_orig_stdin_port);
 
-THREAD_LOCAL fd_set *scheme_fd_set;
+THREAD_LOCAL_DECL(fd_set *scheme_fd_set);
 
 Scheme_Object *(*scheme_make_stdin)(void) = NULL;
 Scheme_Object *(*scheme_make_stdout)(void) = NULL;
@@ -350,11 +350,11 @@ int scheme_force_port_closed;
 static int flush_out;
 static int flush_err;
 
-static THREAD_LOCAL Scheme_Custodian *new_port_cust; /* back-door argument */
+THREAD_LOCAL_DECL(static Scheme_Custodian *new_port_cust); /* back-door argument */
 
 #if defined(FILES_HAVE_FDS)
-static THREAD_LOCAL int external_event_fd;
-static THREAD_LOCAL int put_external_event_fd;
+THREAD_LOCAL_DECL(static int external_event_fd);
+THREAD_LOCAL_DECL(static int put_external_event_fd);
 #endif
 
 static void register_port_wait();
@@ -420,7 +420,7 @@ Scheme_Object *scheme_none_symbol, *scheme_line_symbol, *scheme_block_symbol;
 static Scheme_Object *exact_symbol;
 
 #define READ_STRING_BYTE_BUFFER_SIZE 1024
-static THREAD_LOCAL char *read_string_byte_buffer;
+THREAD_LOCAL_DECL(static char *read_string_byte_buffer);
 
 #define fail_err_symbol scheme_false
 
@@ -8475,7 +8475,7 @@ typedef struct ITimer_Data {
   volatile unsigned long * jit_stack_boundary_ptr;
 } ITimer_Data;
 
-static THREAD_LOCAL ITimer_Data itimerdata;
+THREAD_LOCAL_DECL(static ITimer_Data *itimerdata);
 
 #ifdef MZ_XFORM
 START_XFORM_SKIP;
@@ -8485,6 +8485,8 @@ static void *green_thread_timer(void *data)
 {
   ITimer_Data *itimer_data;
   itimer_data = (ITimer_Data *)data;
+
+  scheme_init_os_thread();
   
   while (1) {
     if (itimer_data->die) {
@@ -8512,54 +8514,63 @@ static void *green_thread_timer(void *data)
 END_XFORM_SKIP;
 #endif
 
-static void start_green_thread_timer(long usec) {
-  itimerdata.die = 0;
-  itimerdata.delay = usec;
-  itimerdata.fuel_counter_ptr = &scheme_fuel_counter;
-  itimerdata.jit_stack_boundary_ptr = &scheme_jit_stack_boundary;
-  pthread_mutex_init(&itimerdata.mutex, NULL);
-  pthread_cond_init(&itimerdata.cond, NULL);
-  pthread_create(&itimerdata.thread, NULL, green_thread_timer, &itimerdata);
-  itimerdata.itimer = 1;
+static void start_green_thread_timer(long usec) 
+{
+  itimerdata->die = 0;
+  itimerdata->delay = usec;
+  itimerdata->fuel_counter_ptr = &scheme_fuel_counter;
+  itimerdata->jit_stack_boundary_ptr = &scheme_jit_stack_boundary;
+  pthread_mutex_init(&itimerdata->mutex, NULL);
+  pthread_cond_init(&itimerdata->cond, NULL);
+  pthread_create(&itimerdata->thread, NULL, green_thread_timer, itimerdata);
+  itimerdata->itimer = 1;
 }
 
-void kill_green_thread_timer() {
-    void *rc;
-    pthread_mutex_lock(&itimerdata.mutex);
-    itimerdata.die = 1;
-    if (!itimerdata.state) {
-      /* itimer thread is currently running working */
-    } else if (itimerdata.state < 0) {
-      /* itimer thread is waiting on cond */
-      pthread_cond_signal(&itimerdata.cond);
-    } else {
-      /* itimer thread is working, and we've already
-         asked it to continue */
-    }
-    pthread_mutex_unlock(&itimerdata.mutex);
-    pthread_join(itimerdata.thread, &rc);
+static void kill_green_thread_timer() 
+{
+  void *rc;
+  pthread_mutex_lock(&itimerdata->mutex);
+  itimerdata->die = 1;
+  if (!itimerdata->state) {
+    /* itimer thread is currently running working */
+  } else if (itimerdata->state < 0) {
+    /* itimer thread is waiting on cond */
+    pthread_cond_signal(&itimerdata->cond);
+  } else {
+    /* itimer thread is working, and we've already
+       asked it to continue */
+  }
+  pthread_mutex_unlock(&itimerdata->mutex);
+  pthread_join(itimerdata->thread, &rc);
+  itimerdata = NULL;
 }
 
-static void kickoff_green_thread_timer(long usec) {
-    pthread_mutex_lock(&itimerdata.mutex);
-    itimerdata.delay = usec;
-    if (!itimerdata.state) {
-      /* itimer thread is currently running working */
-      itimerdata.state = 1;
-    } else if (itimerdata.state < 0) {
-      /* itimer thread is waiting on cond */
-      itimerdata.state = 0;
-      pthread_cond_signal(&itimerdata.cond);
-    } else {
-      /* itimer thread is working, and we've already
-         asked it to continue */
-    }
-    pthread_mutex_unlock(&itimerdata.mutex);
+static void kickoff_green_thread_timer(long usec) 
+{
+  pthread_mutex_lock(&itimerdata->mutex);
+  itimerdata->delay = usec;
+  if (!itimerdata->state) {
+    /* itimer thread is currently running working */
+    itimerdata->state = 1;
+  } else if (itimerdata->state < 0) {
+    /* itimer thread is waiting on cond */
+    itimerdata->state = 0;
+    pthread_cond_signal(&itimerdata->cond);
+  } else {
+    /* itimer thread is working, and we've already
+       asked it to continue */
+  }
+  pthread_mutex_unlock(&itimerdata->mutex);
 }
 
 static void scheme_start_itimer_thread(long usec)
 {
-  if (!itimerdata.itimer) {
+  if (!itimerdata) {
+    itimerdata = (ITimer_Data *)malloc(sizeof(ITimer_Data));
+    memset(itimerdata, 0, sizeof(ITimer_Data));
+  }
+
+  if (!itimerdata->itimer) {
     start_green_thread_timer(usec);
   } else {
     kickoff_green_thread_timer(usec);
@@ -8617,6 +8628,13 @@ void scheme_kickoff_green_thread_time_slice_timer(long usec) {
 #endif
 }
 
+void scheme_kill_green_thread_timer()
+{
+#if defined(USE_PTHREAD_THREAD_TIMER)
+  kill_green_thread_timer();
+#endif
+}
+
 #ifdef OS_X
 
 /* Sleep-in-thread support needed for GUIs Mac OS X.
@@ -8669,6 +8687,7 @@ static void (*sleep_sleep)(float seconds, void *fds);
 
 static void *do_watch()
 {
+  scheme_init_os_thread();
   while (1) {
     pt_sema_wait(&sleeping_sema);
 
diff --git a/src/mzscheme/src/print.c b/src/mzscheme/src/print.c
index a6ed7fcdbb..90c2c3608d 100644
--- a/src/mzscheme/src/print.c
+++ b/src/mzscheme/src/print.c
@@ -35,14 +35,14 @@
 int (*scheme_check_print_is_obj)(Scheme_Object *o);
 
 #define QUICK_ENCODE_BUFFER_SIZE 256
-static THREAD_LOCAL char *quick_buffer = NULL;
-static THREAD_LOCAL char *quick_encode_buffer = NULL;
+THREAD_LOCAL_DECL(static char *quick_buffer = NULL);
+THREAD_LOCAL_DECL(static char *quick_encode_buffer = NULL);
 
 /* FIXME places possible race condition on growing printer size */
 static Scheme_Type_Printer *printers;
 static int printers_count;
 
-static THREAD_LOCAL Scheme_Hash_Table *cache_ht;
+THREAD_LOCAL_DECL(static Scheme_Hash_Table *cache_ht);
 
 /* read-only globals */
 static char compacts[_CPT_COUNT_];
diff --git a/src/mzscheme/src/regexp.c b/src/mzscheme/src/regexp.c
index a018b5f358..d25eecb9e5 100644
--- a/src/mzscheme/src/regexp.c
+++ b/src/mzscheme/src/regexp.c
@@ -66,30 +66,30 @@ static regexp *regcomp(char *, rxpos, int, int);
 /*
  * Global work variables for regcomp().
  */
-static THREAD_LOCAL char *regstr;
-static THREAD_LOCAL char *regparsestr;
-static THREAD_LOCAL int regmatchmin;
-static THREAD_LOCAL int regmatchmax;
-static THREAD_LOCAL int regmaxbackposn;
-static THREAD_LOCAL int regsavepos;
+THREAD_LOCAL_DECL(static char *regstr);
+THREAD_LOCAL_DECL(static char *regparsestr);
+THREAD_LOCAL_DECL(static int regmatchmin);
+THREAD_LOCAL_DECL(static int regmatchmax);
+THREAD_LOCAL_DECL(static int regmaxbackposn);
+THREAD_LOCAL_DECL(static int regsavepos);
 
-static THREAD_LOCAL Scheme_Hash_Table *regbackknown; /* known/assumed backreference [non-]empty */
-static THREAD_LOCAL Scheme_Hash_Table *regbackdepends; /* backreferences required to be non-empty for the current to be non-empty */
+THREAD_LOCAL_DECL(static Scheme_Hash_Table *regbackknown); /* known/assumed backreference [non-]empty */
+THREAD_LOCAL_DECL(static Scheme_Hash_Table *regbackdepends); /* backreferences required to be non-empty for the current to be non-empty */
 
-static THREAD_LOCAL rxpos regparse;
-static THREAD_LOCAL rxpos regparse_end; /* Input-scan pointer. */
-static THREAD_LOCAL int regnpar;             /* () count. */
-static THREAD_LOCAL int regncounter;          /* {} count */
-static THREAD_LOCAL rxpos regcode;           /* Code-emit pointer, if less than regcodesize */
-static THREAD_LOCAL rxpos regcodesize;
-static THREAD_LOCAL rxpos regcodemax;
-static THREAD_LOCAL long regmaxlookback;
+THREAD_LOCAL_DECL(static rxpos regparse);
+THREAD_LOCAL_DECL(static rxpos regparse_end); /* Input-scan pointer. */
+THREAD_LOCAL_DECL(static int regnpar);       /* () count. */
+THREAD_LOCAL_DECL(static int regncounter);   /* {} count */
+THREAD_LOCAL_DECL(static rxpos regcode) ;    /* Code-emit pointer, if less than regcodesize */
+THREAD_LOCAL_DECL(static rxpos regcodesize);
+THREAD_LOCAL_DECL(static rxpos regcodemax);
+THREAD_LOCAL_DECL(static long regmaxlookback);
 
 /* caches to avoid gc */
-static THREAD_LOCAL long rx_buffer_size;
-static THREAD_LOCAL rxpos *startp_buffer_cache;
-static THREAD_LOCAL rxpos *endp_buffer_cache;
-static THREAD_LOCAL rxpos *maybep_buffer_cache;
+THREAD_LOCAL_DECL(static long rx_buffer_size);
+THREAD_LOCAL_DECL(static rxpos *startp_buffer_cache);
+THREAD_LOCAL_DECL(static rxpos *endp_buffer_cache);
+THREAD_LOCAL_DECL(static rxpos *maybep_buffer_cache);
 
 /*
  * Forward declarations for regcomp()'s friends.
diff --git a/src/mzscheme/src/salloc.c b/src/mzscheme/src/salloc.c
index 8b8b124859..4d56f305e4 100644
--- a/src/mzscheme/src/salloc.c
+++ b/src/mzscheme/src/salloc.c
@@ -54,9 +54,13 @@ static void **dgc_array;
 static int *dgc_count;
 static int dgc_size;
 
+#ifdef IMPLEMENT_THREAD_LOCAL_VIA_PTHREADS
+pthread_key_t scheme_thread_local_key;
+#endif
+
 extern int scheme_num_copied_stacks;
 static unsigned long scheme_primordial_os_thread_stack_base;
-static THREAD_LOCAL unsigned long scheme_os_thread_stack_base;
+THREAD_LOCAL_DECL(static unsigned long scheme_os_thread_stack_base);
 
 static Scheme_Report_Out_Of_Memory_Proc more_report_out_of_memory;
 
@@ -151,6 +155,14 @@ int scheme_main_stack_setup(int no_auto_statics, Scheme_Nested_Main _main, void
   void *stack_start;
   int volatile return_code;
 
+#ifdef IMPLEMENT_THREAD_LOCAL_VIA_PTHREADS
+  if (pthread_key_create(&scheme_thread_local_key, NULL)) {
+    fprintf(stderr, "pthread key create failed");
+    abort();
+  }
+  scheme_init_os_thread();
+#endif
+
   scheme_set_stack_base(PROMPT_STACK(stack_start), no_auto_statics);
 
   return_code = _main(data);
@@ -202,6 +214,34 @@ void scheme_set_report_out_of_memory(Scheme_Report_Out_Of_Memory_Proc p)
   more_report_out_of_memory = p;
 }
 
+#ifdef OS_X
+#include <mach/mach.h>
+#endif
+
+#ifdef MZ_XFORM
+START_XFORM_SKIP;
+#endif
+void scheme_init_os_thread()
+{
+#ifdef USE_THREAD_LOCAL
+  Thread_Local_Variables *vars;
+  vars = (Thread_Local_Variables *)malloc(sizeof(Thread_Local_Variables));
+  memset(vars, 0, sizeof(Thread_Local_Variables));
+  pthread_setspecific(scheme_thread_local_key, vars);
+# ifdef OS_X
+  /* A hack that smehow avoids a problem with calling vm_allocate()
+     later. There must be some deeper bug that I have't found, yet. */
+  if (1) {
+    void *r;
+    vm_allocate(mach_task_self(), (vm_address_t*)&r, 4096, TRUE);
+  }
+# endif
+#endif
+}
+#ifdef MZ_XFORM
+END_XFORM_SKIP;
+#endif
+
 /************************************************************************/
 /*                           memory utils                               */
 /************************************************************************/
@@ -998,7 +1038,7 @@ typedef struct Finalization {
   struct Finalization *next, *prev;
 } Finalization;
 
-typedef struct {
+typedef struct Finalizations {
   MZTAG_IF_REQUIRED
   short lifetime;
   Finalization *scheme_first, *scheme_last;
@@ -1066,8 +1106,8 @@ static void do_next_finalization(void *o, void *data)
 
 /* Makes gc2 xformer happy: */
 typedef void (*finalizer_function)(void *p, void *data);
-static THREAD_LOCAL int traversers_registered;
-static THREAD_LOCAL Finalizations **save_fns_ptr;
+THREAD_LOCAL_DECL(static int traversers_registered);
+THREAD_LOCAL_DECL(static Finalizations **save_fns_ptr);
 
 static void add_finalizer(void *v, void (*f)(void*,void*), void *data, 
 			  int prim, int ext,
diff --git a/src/mzscheme/src/schemef.h b/src/mzscheme/src/schemef.h
index 6ee569f92c..7208c87d43 100644
--- a/src/mzscheme/src/schemef.h
+++ b/src/mzscheme/src/schemef.h
@@ -67,14 +67,14 @@ MZ_EXTERN Scheme_Object *scheme_current_break_cell();
 /*                                threads                                 */
 /*========================================================================*/
 
-#ifndef LINK_EXTENSIONS_BY_TABLE
-# if !defined(MZ_USE_PLACES) || !defined(FUTURES_ENABLED)
-MZ_EXTERN THREAD_LOCAL Scheme_Thread *scheme_current_thread;
-# endif
-MZ_EXTERN THREAD_LOCAL volatile int scheme_fuel_counter;
-#else
+#ifndef USE_THREAD_LOCAL
+# ifndef LINK_EXTENSIONS_BY_TABLE
+MZ_EXTERN Scheme_Thread *scheme_current_thread;
+MZ_EXTERN volatile int scheme_fuel_counter;
+# else
 MZ_EXTERN Scheme_Thread **scheme_current_thread_ptr;
 MZ_EXTERN volatile int *scheme_fuel_counter_ptr;
+# endif
 #endif
 
 MZ_EXTERN Scheme_Thread *scheme_get_current_thread();
@@ -407,7 +407,9 @@ MZ_EXTERN void scheme_gc_ptr_ok(void *p);
 MZ_EXTERN void scheme_collect_garbage(void);
 
 #ifdef MZ_PRECISE_GC
-MZ_EXTERN THREAD_LOCAL void **GC_variable_stack;
+# ifndef USE_THREAD_LOCAL
+MZ_EXTERN void **GC_variable_stack;
+# endif
 MZ_EXTERN void GC_register_traversers(short tag, Size_Proc size, Mark_Proc mark, Fixup_Proc fixup,
 				      int is_constant_size, int is_atomic);
 MZ_EXTERN void *GC_resolve(void *p);
diff --git a/src/mzscheme/src/schemex.h b/src/mzscheme/src/schemex.h
index be20335c54..9d6f79b6b4 100644
--- a/src/mzscheme/src/schemex.h
+++ b/src/mzscheme/src/schemex.h
@@ -53,14 +53,14 @@ Scheme_Object *(*scheme_current_break_cell)();
 /*========================================================================*/
 /*                                threads                                 */
 /*========================================================================*/
-#ifndef LINK_EXTENSIONS_BY_TABLE
-# if !defined(MZ_USE_PLACES) || !defined(FUTURES_ENABLED)
+#ifndef USE_THREAD_LOCAL
+# ifndef LINK_EXTENSIONS_BY_TABLE
 Scheme_Thread *scheme_current_thread;
-# endif
 volatile int scheme_fuel_counter;
-#else
+# else
 Scheme_Thread **scheme_current_thread_ptr;
 volatile int *scheme_fuel_counter_ptr;
+# endif
 #endif
 Scheme_Thread *(*scheme_get_current_thread)();
 void (*scheme_start_atomic)(void);
@@ -329,7 +329,9 @@ void (*scheme_dont_gc_ptr)(void *p);
 void (*scheme_gc_ptr_ok)(void *p);
 void (*scheme_collect_garbage)(void);
 #ifdef MZ_PRECISE_GC
+# ifndef USE_THREAD_LOCAL
 void **GC_variable_stack;
+# endif
 void (*GC_register_traversers)(short tag, Size_Proc size, Mark_Proc mark, Fixup_Proc fixup,
 				      int is_constant_size, int is_atomic);
 void *(*GC_resolve)(void *p);
diff --git a/src/mzscheme/src/schemex.inc b/src/mzscheme/src/schemex.inc
index 35233fda6e..da7bbba87d 100644
--- a/src/mzscheme/src/schemex.inc
+++ b/src/mzscheme/src/schemex.inc
@@ -18,14 +18,14 @@
   scheme_extension_table->scheme_get_env = scheme_get_env;
   scheme_extension_table->scheme_inherit_cells = scheme_inherit_cells;
   scheme_extension_table->scheme_current_break_cell = scheme_current_break_cell;
-#ifndef LINK_EXTENSIONS_BY_TABLE
-# if !defined(MZ_USE_PLACES) || !defined(FUTURES_ENABLED)
+#ifndef USE_THREAD_LOCAL
+# ifndef LINK_EXTENSIONS_BY_TABLE
   scheme_extension_table->scheme_current_thread = scheme_current_thread;
-# endif
   scheme_extension_table->scheme_fuel_counter = scheme_fuel_counter;
-#else
+# else
   scheme_extension_table->scheme_current_thread_ptr = scheme_current_thread_ptr;
   scheme_extension_table->scheme_fuel_counter_ptr = scheme_fuel_counter_ptr;
+# endif
 #endif
   scheme_extension_table->scheme_get_current_thread = scheme_get_current_thread;
   scheme_extension_table->scheme_start_atomic = scheme_start_atomic;
@@ -229,7 +229,9 @@
   scheme_extension_table->scheme_gc_ptr_ok = scheme_gc_ptr_ok;
   scheme_extension_table->scheme_collect_garbage = scheme_collect_garbage;
 #ifdef MZ_PRECISE_GC
+# ifndef USE_THREAD_LOCAL
   scheme_extension_table->GC_variable_stack = GC_variable_stack;
+# endif
   scheme_extension_table->GC_register_traversers = GC_register_traversers;
   scheme_extension_table->GC_resolve = GC_resolve;
   scheme_extension_table->GC_mark = GC_mark;
diff --git a/src/mzscheme/src/schemexm.h b/src/mzscheme/src/schemexm.h
index ba5deb8927..8bfafb6c5d 100644
--- a/src/mzscheme/src/schemexm.h
+++ b/src/mzscheme/src/schemexm.h
@@ -18,14 +18,14 @@
 #define scheme_get_env (scheme_extension_table->scheme_get_env)
 #define scheme_inherit_cells (scheme_extension_table->scheme_inherit_cells)
 #define scheme_current_break_cell (scheme_extension_table->scheme_current_break_cell)
-#ifndef LINK_EXTENSIONS_BY_TABLE
-# if !defined(MZ_USE_PLACES) || !defined(FUTURES_ENABLED)
+#ifndef USE_THREAD_LOCAL
+# ifndef LINK_EXTENSIONS_BY_TABLE
 #define scheme_current_thread (scheme_extension_table->scheme_current_thread)
-# endif
 #define scheme_fuel_counter (scheme_extension_table->scheme_fuel_counter)
-#else
+# else
 #define scheme_current_thread_ptr (scheme_extension_table->scheme_current_thread_ptr)
 #define scheme_fuel_counter_ptr (scheme_extension_table->scheme_fuel_counter_ptr)
+# endif
 #endif
 #define scheme_get_current_thread (scheme_extension_table->scheme_get_current_thread)
 #define scheme_start_atomic (scheme_extension_table->scheme_start_atomic)
@@ -229,7 +229,9 @@
 #define scheme_gc_ptr_ok (scheme_extension_table->scheme_gc_ptr_ok)
 #define scheme_collect_garbage (scheme_extension_table->scheme_collect_garbage)
 #ifdef MZ_PRECISE_GC
+# ifndef USE_THREAD_LOCAL
 #define GC_variable_stack (scheme_extension_table->GC_variable_stack)
+# endif
 #define GC_register_traversers (scheme_extension_table->GC_register_traversers)
 #define GC_resolve (scheme_extension_table->GC_resolve)
 #define GC_mark (scheme_extension_table->GC_mark)
diff --git a/src/mzscheme/src/schfd.h b/src/mzscheme/src/schfd.h
index b0d081b510..63638f9724 100644
--- a/src/mzscheme/src/schfd.h
+++ b/src/mzscheme/src/schfd.h
@@ -1,6 +1,6 @@
 
 #ifdef USE_FAR_MZ_FDCALLS
-extern THREAD_LOCAL fd_set *scheme_fd_set;
+THREAD_LOCAL_DECL(extern fd_set *scheme_fd_set);
 # define DECL_FDSET(n, c) fd_set *n
 # define INIT_DECL_FDSET(r, w, e) { \
     r = MZ_GET_FDSET(scheme_fd_set, 0 ); \
diff --git a/src/mzscheme/src/schpriv.h b/src/mzscheme/src/schpriv.h
index 840c0f4d3e..9c4c2dc981 100644
--- a/src/mzscheme/src/schpriv.h
+++ b/src/mzscheme/src/schpriv.h
@@ -91,8 +91,8 @@ Scheme_Object *scheme_dump_gc_stats(int c, Scheme_Object *p[]);
 #define REGISTER_SO(x) MZ_REGISTER_STATIC(x)
 
 extern long scheme_total_gc_time;
-extern THREAD_LOCAL int scheme_cont_capture_count;
-extern THREAD_LOCAL int scheme_continuation_application_count;
+THREAD_LOCAL_DECL(extern int scheme_cont_capture_count);
+THREAD_LOCAL_DECL(extern int scheme_continuation_application_count);
 
 int scheme_num_types(void);
 
@@ -224,6 +224,7 @@ void scheme_init_foreign_globals();
 void scheme_init_foreign(Scheme_Env *env);
 #endif
 void scheme_init_place(Scheme_Env *env);
+void scheme_init_futures(Scheme_Env *env);
 
 void scheme_init_print_buffers_places(void);
 void scheme_init_eval_places(void);
@@ -307,9 +308,9 @@ extern Scheme_Object *scheme_equal_prim;
 
 extern Scheme_Object *scheme_def_exit_proc;
 
-extern THREAD_LOCAL Scheme_Object *scheme_orig_stdout_port;
-extern THREAD_LOCAL Scheme_Object *scheme_orig_stdin_port;
-extern THREAD_LOCAL Scheme_Object *scheme_orig_stderr_port;
+THREAD_LOCAL_DECL(extern Scheme_Object *scheme_orig_stdout_port);
+THREAD_LOCAL_DECL(extern Scheme_Object *scheme_orig_stdin_port);
+THREAD_LOCAL_DECL(extern Scheme_Object *scheme_orig_stderr_port);
 
 extern Scheme_Object *scheme_arity_at_least, *scheme_make_arity_at_least;
 
@@ -335,7 +336,7 @@ extern Scheme_Object *scheme_stack_dump_key;
 
 extern Scheme_Object *scheme_default_prompt_tag;
 
-extern THREAD_LOCAL Scheme_Object *scheme_system_idle_channel;
+THREAD_LOCAL_DECL(extern Scheme_Object *scheme_system_idle_channel);
 
 extern Scheme_Object *scheme_input_port_property, *scheme_output_port_property;
 
@@ -350,10 +351,10 @@ extern Scheme_Object *scheme_reduced_procedure_struct;
 #define RUNSTACK_IS_GLOBAL
 
 #ifdef RUNSTACK_IS_GLOBAL
-extern THREAD_LOCAL Scheme_Object **scheme_current_runstack;
-extern THREAD_LOCAL Scheme_Object **scheme_current_runstack_start;
-extern THREAD_LOCAL MZ_MARK_STACK_TYPE scheme_current_cont_mark_stack;
-extern THREAD_LOCAL MZ_MARK_POS_TYPE scheme_current_cont_mark_pos;
+THREAD_LOCAL_DECL(extern Scheme_Object **scheme_current_runstack);
+THREAD_LOCAL_DECL(extern Scheme_Object **scheme_current_runstack_start);
+THREAD_LOCAL_DECL(extern MZ_MARK_STACK_TYPE scheme_current_cont_mark_stack);
+THREAD_LOCAL_DECL(extern MZ_MARK_POS_TYPE scheme_current_cont_mark_pos);
 # define MZ_RUNSTACK scheme_current_runstack
 # define MZ_RUNSTACK_START scheme_current_runstack_start
 # define MZ_CONT_MARK_STACK scheme_current_cont_mark_stack
@@ -365,13 +366,13 @@ extern THREAD_LOCAL MZ_MARK_POS_TYPE scheme_current_cont_mark_pos;
 # define MZ_CONT_MARK_POS (scheme_current_thread->cont_mark_pos)
 #endif
 
-extern THREAD_LOCAL volatile int scheme_fuel_counter;
+THREAD_LOCAL_DECL(extern volatile int scheme_fuel_counter);
 
-extern THREAD_LOCAL Scheme_Thread *scheme_main_thread;
+THREAD_LOCAL_DECL(extern Scheme_Thread *scheme_main_thread);
 
 #ifdef MZ_USE_PLACES
-extern THREAD_LOCAL Scheme_Thread *scheme_current_thread;
-extern THREAD_LOCAL Scheme_Thread *scheme_first_thread;
+THREAD_LOCAL_DECL(extern Scheme_Thread *scheme_current_thread);
+THREAD_LOCAL_DECL(extern Scheme_Thread *scheme_first_thread);
 #define scheme_eval_wait_expr (scheme_current_thread->ku.eval.wait_expr)
 #define scheme_tail_rator (scheme_current_thread->ku.apply.tail_rator)
 #define scheme_tail_num_rands (scheme_current_thread->ku.apply.tail_num_rands)
@@ -383,10 +384,10 @@ extern THREAD_LOCAL Scheme_Thread *scheme_first_thread;
 #define scheme_multiple_array (scheme_current_thread->ku.multiple.array)
 #include "mzrt.h"
 extern mz_proc_thread *scheme_master_proc_thread;
-extern THREAD_LOCAL mz_proc_thread *proc_thread_self;
+THREAD_LOCAL_DECL(extern mz_proc_thread *proc_thread_self);
 #endif
 
-extern THREAD_LOCAL int scheme_no_stack_overflow;
+THREAD_LOCAL_DECL(extern int scheme_no_stack_overflow);
 
 typedef struct Scheme_Thread_Set {
   Scheme_Object so;
@@ -398,7 +399,7 @@ typedef struct Scheme_Thread_Set {
   Scheme_Object *current;
 } Scheme_Thread_Set;
 
-extern THREAD_LOCAL Scheme_Thread_Set *scheme_thread_set_top;
+THREAD_LOCAL_DECL(extern Scheme_Thread_Set *scheme_thread_set_top);
 
 #define SCHEME_TAIL_COPY_THRESHOLD 5
 
@@ -1081,8 +1082,8 @@ void scheme_notify_code_gc(void);
 
 Scheme_Object *scheme_handle_stack_overflow(Scheme_Object *(*k)(void));
 
-extern THREAD_LOCAL struct Scheme_Overflow_Jmp *scheme_overflow_jmp;
-extern THREAD_LOCAL void *scheme_overflow_stack_start;
+THREAD_LOCAL_DECL(extern struct Scheme_Overflow_Jmp *scheme_overflow_jmp);
+THREAD_LOCAL_DECL(extern void *scheme_overflow_stack_start);
 
 #ifdef MZ_PRECISE_GC
 # define PROMPT_STACK(id) &__gc_var_stack__
@@ -1284,10 +1285,10 @@ typedef struct Scheme_Overflow {
     || defined(BEOS_FIND_STACK_BOUNDS) || defined(OSKIT_FIXED_STACK_BOUNDS) \
     || defined(PALM_FIND_STACK_BOUNDS)
 # define USE_STACK_BOUNDARY_VAR
-extern THREAD_LOCAL unsigned long scheme_stack_boundary;
+THREAD_LOCAL_DECL(extern unsigned long scheme_stack_boundary);
 /* Same as scheme_stack_boundary, but set to an extreme value when feul auto-expires,
    so that JIT-generated code can check just one variable: */
-extern THREAD_LOCAL unsigned long volatile scheme_jit_stack_boundary;
+THREAD_LOCAL_DECL(extern unsigned long volatile scheme_jit_stack_boundary);
 #endif
 
 typedef struct Scheme_Meta_Continuation {
@@ -1459,7 +1460,7 @@ typedef struct {
   bigdig *digits;
 } Scheme_Bignum;
 
-#if MZ_PRECISE_GC
+#ifdef MZ_PRECISE_GC
 # define SCHEME_BIGPOS(b) (MZ_OPT_HASH_KEY(&((Scheme_Bignum *)b)->iso) & 0x1)
 # define SCHEME_SET_BIGPOS(b, v) MZ_OPT_HASH_KEY(&((Scheme_Bignum *)b)->iso) = ((v) | SCHEME_BIGINLINE(b))
 # define SCHEME_BIGINLINE(b) (MZ_OPT_HASH_KEY(&((Scheme_Bignum *)b)->iso) & 0x2)
@@ -3047,7 +3048,7 @@ extern char *scheme_convert_from_wchar(const wchar_t *ws);
 # define USE_SOCKETS_TCP
 #endif
 
-extern THREAD_LOCAL int scheme_active_but_sleeping;
+THREAD_LOCAL_DECL(extern int scheme_active_but_sleeping);
 extern int scheme_file_open_count;
 
 typedef struct Scheme_Indexed_String {
@@ -3256,7 +3257,7 @@ typedef struct Scheme_Place {
 
 Scheme_Env *scheme_place_instance_init();
 void scheme_place_instance_destroy();
-void kill_green_thread_timer();
+void scheme_kill_green_thread_timer();
 
 /*========================================================================*/
 /*                           engine                                       */
diff --git a/src/mzscheme/src/schrx.h b/src/mzscheme/src/schrx.h
index 13f3e01738..1c08f83dc6 100644
--- a/src/mzscheme/src/schrx.h
+++ b/src/mzscheme/src/schrx.h
@@ -5,8 +5,6 @@
    once, anyway.) */
 /* #define INDIRECT_TO_PROGRAM */
 
-typedef long rxpos;
-
 struct Regwork;
 
 typedef int (*Scheme_Regexp_Matcher)(struct Regwork *rw);
diff --git a/src/mzscheme/src/schvers.h b/src/mzscheme/src/schvers.h
index a8c0b092a5..a7586b1a72 100644
--- a/src/mzscheme/src/schvers.h
+++ b/src/mzscheme/src/schvers.h
@@ -13,12 +13,12 @@
    consistently.)
 */
 
-#define MZSCHEME_VERSION "4.2.3.1"
+#define MZSCHEME_VERSION "4.2.3.2"
 
 #define MZSCHEME_VERSION_X 4
 #define MZSCHEME_VERSION_Y 2
 #define MZSCHEME_VERSION_Z 3
-#define MZSCHEME_VERSION_W 1
+#define MZSCHEME_VERSION_W 2
 
 #define MZSCHEME_VERSION_MAJOR ((MZSCHEME_VERSION_X * 100) + MZSCHEME_VERSION_Y)
 #define MZSCHEME_VERSION_MINOR ((MZSCHEME_VERSION_Z * 1000) + MZSCHEME_VERSION_W)
diff --git a/src/mzscheme/src/sema.c b/src/mzscheme/src/sema.c
index cb4d01323a..d4faf7091d 100644
--- a/src/mzscheme/src/sema.c
+++ b/src/mzscheme/src/sema.c
@@ -24,7 +24,7 @@
 #ifndef NO_SCHEME_THREADS
 
 Scheme_Object *scheme_always_ready_evt;
-THREAD_LOCAL Scheme_Object *scheme_system_idle_channel;
+THREAD_LOCAL_DECL(Scheme_Object *scheme_system_idle_channel);
 
 static Scheme_Object *make_sema(int n, Scheme_Object **p);
 static Scheme_Object *semap(int n, Scheme_Object **p);
@@ -59,7 +59,7 @@ static int pending_break(Scheme_Thread *p);
 
 int scheme_main_was_once_suspended;
 
-static THREAD_LOCAL Scheme_Object *system_idle_put_evt;
+THREAD_LOCAL_DECL(static Scheme_Object *system_idle_put_evt);
 static Scheme_Object *thread_recv_evt;
 
 #ifdef MZ_PRECISE_GC
diff --git a/src/mzscheme/src/setjmpup.c b/src/mzscheme/src/setjmpup.c
index 6eb98b31e1..90807ca0d1 100644
--- a/src/mzscheme/src/setjmpup.c
+++ b/src/mzscheme/src/setjmpup.c
@@ -216,10 +216,9 @@ static void set_copy(void *s_c, void *c)
 # define get_copy(s_c) (s_c)
 # define set_copy(s_c, c) s_c = c
 
-#define STACK_COPY_CACHE_SIZE 10
-static THREAD_LOCAL void *stack_copy_cache[STACK_COPY_CACHE_SIZE];
-static THREAD_LOCAL long stack_copy_size_cache[STACK_COPY_CACHE_SIZE];
-static THREAD_LOCAL int scc_pos;
+THREAD_LOCAL_DECL(static void *stack_copy_cache[STACK_COPY_CACHE_SIZE]);
+THREAD_LOCAL_DECL(static long stack_copy_size_cache[STACK_COPY_CACHE_SIZE]);
+THREAD_LOCAL_DECL(static int scc_pos);
 #define SCC_OK_EXTRA_AMT 100
 
 START_XFORM_SKIP;
diff --git a/src/mzscheme/src/startup.inc b/src/mzscheme/src/startup.inc
index 7c8c60286f..b328b3eddc 100644
--- a/src/mzscheme/src/startup.inc
+++ b/src/mzscheme/src/startup.inc
@@ -395,7 +395,8 @@
 " '#%paramz"
 " '#%network"
 " '#%utils"
-"(only '#%place)))"
+"(only '#%place)"
+"(only '#%futures)))"
 );
   EVAL_ONE_STR(
 "(module #%boot '#%kernel"
diff --git a/src/mzscheme/src/startup.ss b/src/mzscheme/src/startup.ss
index 15e1185570..55f00b6311 100644
--- a/src/mzscheme/src/startup.ss
+++ b/src/mzscheme/src/startup.ss
@@ -469,7 +469,8 @@
              '#%paramz
              '#%network
              '#%utils
-             (only '#%place)))
+             (only '#%place)
+             (only '#%futures)))
 
 ;; ----------------------------------------
 ;; Handlers to install on startup
diff --git a/src/mzscheme/src/struct.c b/src/mzscheme/src/struct.c
index 0b6a040b3d..922ee76e37 100644
--- a/src/mzscheme/src/struct.c
+++ b/src/mzscheme/src/struct.c
@@ -146,7 +146,7 @@ static Scheme_Object *scheme_checked_proc_property;
 static void register_traversers(void);
 #endif
 
-static THREAD_LOCAL Scheme_Bucket_Table *prefab_table;
+THREAD_LOCAL_DECL(static Scheme_Bucket_Table *prefab_table);
 static Scheme_Object *make_prefab_key(Scheme_Struct_Type *type);
 
 #define cons scheme_make_pair
diff --git a/src/mzscheme/src/stxobj.c b/src/mzscheme/src/stxobj.c
index 3cd2cc0512..76c90aea1e 100644
--- a/src/mzscheme/src/stxobj.c
+++ b/src/mzscheme/src/stxobj.c
@@ -82,25 +82,25 @@ static Scheme_Object *lexical_symbol;
 static Scheme_Object *protected_symbol;
 static Scheme_Object *nominal_id_symbol;
 
-static THREAD_LOCAL Scheme_Object *nominal_ipair_cache;
+THREAD_LOCAL_DECL(static Scheme_Object *nominal_ipair_cache);
 
-static THREAD_LOCAL Scheme_Object *mark_id = scheme_make_integer(0);
-static THREAD_LOCAL Scheme_Object *current_rib_timestamp = scheme_make_integer(0);
+THREAD_LOCAL_DECL(static Scheme_Object *mark_id);
+THREAD_LOCAL_DECL(static Scheme_Object *current_rib_timestamp);
 
 static Scheme_Stx_Srcloc *empty_srcloc;
 
 static Scheme_Object *empty_simplified;
 
-static THREAD_LOCAL Scheme_Hash_Table *quick_hash_table;
+THREAD_LOCAL_DECL(static Scheme_Hash_Table *quick_hash_table);
 
-static THREAD_LOCAL Scheme_Object *last_phase_shift;
+THREAD_LOCAL_DECL(static Scheme_Object *last_phase_shift);
 
-static THREAD_LOCAL Scheme_Object *unsealed_dependencies;
+THREAD_LOCAL_DECL(static Scheme_Object *unsealed_dependencies);
 
-static THREAD_LOCAL Scheme_Hash_Table *id_marks_ht; /* a cache */
-static THREAD_LOCAL Scheme_Hash_Table *than_id_marks_ht; /* a cache */
+THREAD_LOCAL_DECL(static Scheme_Hash_Table *id_marks_ht); /* a cache */
+THREAD_LOCAL_DECL(static Scheme_Hash_Table *than_id_marks_ht); /* a cache */
 
-static THREAD_LOCAL Scheme_Bucket_Table *interned_skip_ribs;
+THREAD_LOCAL_DECL(static Scheme_Bucket_Table *interned_skip_ribs);
 
 static Scheme_Object *no_nested_inactive_certs;
 
@@ -602,6 +602,9 @@ void scheme_init_stx(Scheme_Env *env)
   nominal_id_symbol = scheme_intern_symbol("nominal-id");
 
   REGISTER_SO(mark_id);
+  REGISTER_SO(current_rib_timestamp);
+  mark_id = scheme_make_integer(0);
+  current_rib_timestamp = scheme_make_integer(0);
 
   REGISTER_SO(empty_srcloc);
   empty_srcloc = MALLOC_ONE_RT(Scheme_Stx_Srcloc);
diff --git a/src/mzscheme/src/thread.c b/src/mzscheme/src/thread.c
index d70b0d88bf..1fa87713cd 100644
--- a/src/mzscheme/src/thread.c
+++ b/src/mzscheme/src/thread.c
@@ -140,40 +140,40 @@ extern int scheme_jit_malloced;
 
 static int buffer_init_size = INIT_TB_SIZE;
 
-THREAD_LOCAL Scheme_Thread *scheme_current_thread = NULL;
-THREAD_LOCAL Scheme_Thread *scheme_main_thread = NULL;
-THREAD_LOCAL Scheme_Thread *scheme_first_thread = NULL;
+THREAD_LOCAL_DECL(Scheme_Thread *scheme_current_thread = NULL);
+THREAD_LOCAL_DECL(Scheme_Thread *scheme_main_thread = NULL);
+THREAD_LOCAL_DECL(Scheme_Thread *scheme_first_thread = NULL);
 
 Scheme_Thread *scheme_get_current_thread() { return scheme_current_thread; }
 long scheme_get_multiple_count() { return scheme_current_thread->ku.multiple.count; }
 Scheme_Object **scheme_get_multiple_array() { return scheme_current_thread->ku.multiple.array; }
 void scheme_set_current_thread_ran_some() { scheme_current_thread->ran_some = 1; }
 
-THREAD_LOCAL Scheme_Thread_Set *scheme_thread_set_top;
+THREAD_LOCAL_DECL(Scheme_Thread_Set *scheme_thread_set_top);
 
-static THREAD_LOCAL int num_running_threads = 1;
+THREAD_LOCAL_DECL(static int num_running_threads); /* not counting original */
 
 #ifdef LINK_EXTENSIONS_BY_TABLE
 Scheme_Thread **scheme_current_thread_ptr;
 volatile int *scheme_fuel_counter_ptr;
 #endif
-static THREAD_LOCAL int swap_no_setjmp = 0;
+THREAD_LOCAL_DECL(static int swap_no_setjmp = 0);
 
-static THREAD_LOCAL int thread_swap_count;
-static THREAD_LOCAL int did_gc_count;
+THREAD_LOCAL_DECL(static int thread_swap_count);
+THREAD_LOCAL_DECL(static int did_gc_count);
 
 static int init_load_on_demand = 1;
 
 #ifdef RUNSTACK_IS_GLOBAL
-THREAD_LOCAL Scheme_Object **scheme_current_runstack_start;
-THREAD_LOCAL Scheme_Object **scheme_current_runstack;
-THREAD_LOCAL MZ_MARK_STACK_TYPE scheme_current_cont_mark_stack;
-THREAD_LOCAL MZ_MARK_POS_TYPE scheme_current_cont_mark_pos;
+THREAD_LOCAL_DECL(Scheme_Object **scheme_current_runstack_start);
+THREAD_LOCAL_DECL(Scheme_Object **scheme_current_runstack);
+THREAD_LOCAL_DECL(MZ_MARK_STACK_TYPE scheme_current_cont_mark_stack);
+THREAD_LOCAL_DECL(MZ_MARK_POS_TYPE scheme_current_cont_mark_pos);
 #endif
 
-static THREAD_LOCAL Scheme_Custodian *main_custodian;
-static THREAD_LOCAL Scheme_Custodian *last_custodian;
-static THREAD_LOCAL Scheme_Hash_Table *limited_custodians = NULL;
+THREAD_LOCAL_DECL(static Scheme_Custodian *main_custodian);
+THREAD_LOCAL_DECL(static Scheme_Custodian *last_custodian);
+THREAD_LOCAL_DECL(static Scheme_Hash_Table *limited_custodians = NULL);
 
 static Scheme_Object *initial_inspector;
 
@@ -188,9 +188,9 @@ extern int GC_is_marked(void *);
 /* On swap, put target in a static variable, instead of on the stack,
    so that the swapped-out thread is less likely to have a pointer
    to the target thread. */
-static THREAD_LOCAL Scheme_Thread *swap_target;
+THREAD_LOCAL_DECL(static Scheme_Thread *swap_target);
 
-static THREAD_LOCAL Scheme_Object *scheduled_kills;
+THREAD_LOCAL_DECL(static Scheme_Object *scheduled_kills);
 
 Scheme_Object *scheme_parameterization_key;
 Scheme_Object *scheme_exn_handler_key;
@@ -213,16 +213,16 @@ void (*scheme_wakeup_on_input)(void *fds);
 int (*scheme_check_for_break)(void);
 void (*scheme_on_atomic_timeout)(void);
 
-static THREAD_LOCAL int do_atomic = 0;
-static THREAD_LOCAL int missed_context_switch = 0;
-static THREAD_LOCAL int have_activity = 0;
-THREAD_LOCAL int scheme_active_but_sleeping = 0;
-static THREAD_LOCAL int thread_ended_with_activity;
-THREAD_LOCAL int scheme_no_stack_overflow;
+THREAD_LOCAL_DECL(static int do_atomic = 0);
+THREAD_LOCAL_DECL(static int missed_context_switch = 0);
+THREAD_LOCAL_DECL(static int have_activity = 0);
+THREAD_LOCAL_DECL(int scheme_active_but_sleeping = 0);
+THREAD_LOCAL_DECL(static int thread_ended_with_activity);
+THREAD_LOCAL_DECL(int scheme_no_stack_overflow);
 
-static THREAD_LOCAL int needs_sleep_cancelled;
+THREAD_LOCAL_DECL(static int needs_sleep_cancelled);
 
-static THREAD_LOCAL int tls_pos = 0;
+THREAD_LOCAL_DECL(static int tls_pos = 0);
 
 #ifdef MZ_PRECISE_GC
 extern long GC_get_memory_use(void *c);
@@ -245,17 +245,18 @@ typedef struct Thread_Cell {
 static Scheme_Object *read_symbol, *write_symbol, *execute_symbol, *delete_symbol, *exists_symbol;
 static Scheme_Object *client_symbol, *server_symbol;
 
-static THREAD_LOCAL Scheme_Object *nested_exn_handler;
+THREAD_LOCAL_DECL(static Scheme_Object *the_nested_exn_handler);
 
-static THREAD_LOCAL Scheme_Object *closers;
+THREAD_LOCAL_DECL(static Scheme_Object *cust_closers);
 
-static THREAD_LOCAL Scheme_Object *thread_swap_callbacks,  *thread_swap_out_callbacks;
+THREAD_LOCAL_DECL(static Scheme_Object *thread_swap_callbacks);
+THREAD_LOCAL_DECL(static Scheme_Object *thread_swap_out_callbacks);
 
-static THREAD_LOCAL Scheme_Object *recycle_cell;
-static THREAD_LOCAL Scheme_Object *maybe_recycle_cell;
-static THREAD_LOCAL int recycle_cc_count;
-	
-static THREAD_LOCAL mz_jmp_buf main_init_error_buf;
+THREAD_LOCAL_DECL(static Scheme_Object *recycle_cell);
+THREAD_LOCAL_DECL(static Scheme_Object *maybe_recycle_cell);
+THREAD_LOCAL_DECL(static int recycle_cc_count);
+
+THREAD_LOCAL_DECL(static mz_jmp_buf main_init_error_buf);
 	
 #ifdef MZ_PRECISE_GC
 /* This is a trick to get the types right. Note that 
@@ -1888,7 +1889,7 @@ static void run_closers(Scheme_Object *o, Scheme_Close_Custodian_Client *f, void
 {
   Scheme_Object *l;
 
-  for (l = closers; SCHEME_RPAIRP(l); l = SCHEME_CDR(l)) {
+  for (l = cust_closers; SCHEME_RPAIRP(l); l = SCHEME_CDR(l)) {
     Scheme_Exit_Closer_Func cf;
     cf = (Scheme_Exit_Closer_Func)SCHEME_CAR(l);
     cf(o, f, data);
@@ -1915,18 +1916,18 @@ static void run_atexit_closers(void)
 
 void scheme_add_atexit_closer(Scheme_Exit_Closer_Func f)
 {
-  if (!closers) {
+  if (!cust_closers) {
 #ifdef USE_ON_EXIT_FOR_ATEXIT
     on_exit(run_atexit_closers, NULL);
 #else
     atexit(run_atexit_closers);
 #endif
 
-    REGISTER_SO(closers);
-    closers = scheme_null;
+    REGISTER_SO(cust_closers);
+    cust_closers = scheme_null;
   }
 
-  closers = scheme_make_raw_pair((Scheme_Object *)f, closers);
+  cust_closers = scheme_make_raw_pair((Scheme_Object *)f, cust_closers);
 }
 
 void scheme_schedule_custodian_close(Scheme_Custodian *c)
@@ -3374,13 +3375,13 @@ Scheme_Object *scheme_call_as_nested_thread(int argc, Scheme_Object *argv[], voi
   if (p != scheme_main_thread)
     scheme_weak_suspend_thread(p);
 
-  if (!nested_exn_handler) {
-    REGISTER_SO(nested_exn_handler);
-    nested_exn_handler = scheme_make_prim_w_arity(def_nested_exn_handler,
-                                                  "nested-thread-exception-handler",
-                                                  1, 1);
+  if (!the_nested_exn_handler) {
+    REGISTER_SO(the_nested_exn_handler);
+    the_nested_exn_handler = scheme_make_prim_w_arity(def_nested_exn_handler,
+                                                      "nested-thread-exception-handler",
+                                                      1, 1);
   }
-  scheme_set_cont_mark(scheme_exn_handler_key, nested_exn_handler);
+  scheme_set_cont_mark(scheme_exn_handler_key, the_nested_exn_handler);
 
   /* Call thunk, catch escape: */
   np->error_buf = &newbuf;
@@ -7568,7 +7569,7 @@ static Scheme_Object *current_stats(int argc, Scheme_Object *argv[])
     case 8:
       SCHEME_VEC_ELS(v)[7] = scheme_make_integer(scheme_num_read_syntax_objects);
     case 7:
-      SCHEME_VEC_ELS(v)[6] = scheme_make_integer(num_running_threads);
+      SCHEME_VEC_ELS(v)[6] = scheme_make_integer(num_running_threads+1);
     case 6:
       SCHEME_VEC_ELS(v)[5] = scheme_make_integer(scheme_overflow_count);
     case 5:
diff --git a/src/worksp/gc2/make.ss b/src/worksp/gc2/make.ss
index 24cf69158d..a0b450098d 100644
--- a/src/worksp/gc2/make.ss
+++ b/src/worksp/gc2/make.ss
@@ -35,6 +35,7 @@
     "error"
     "eval"
     "file"
+    "future"
     "fun"
     "hash"
     "jit"
diff --git a/src/worksp/libmzsch/libmzsch.vcproj b/src/worksp/libmzsch/libmzsch.vcproj
index 2fa2ae4202..0a03068aa1 100644
--- a/src/worksp/libmzsch/libmzsch.vcproj
+++ b/src/worksp/libmzsch/libmzsch.vcproj
@@ -246,6 +246,10 @@
 				RelativePath="..\..\Mzscheme\Src\Fun.c"
 				>
 			</File>
+			<File
+				RelativePath="..\..\Mzscheme\Src\Future.c"
+				>
+			</File>
 			<File
 				RelativePath="..\..\Mzscheme\Src\gmp\gmp.c"
 				>