diff --git a/src/configure b/src/configure
index 1fa9ac9ae4..bb6e5d7f93 100755
--- a/src/configure
+++ b/src/configure
@@ -3938,6 +3938,13 @@ if test "${enable_shared}" = "yes" ; then
   LIBRACKET_DEP="${LIBRACKET_DEP} libmzgc.la"
 fi
 
+if test "${enable_foreign}" = "yes" ; then
+  check_for_mprotect=yes
+fi
+if test "${enable_jit}" = "yes" ; then
+  check_for_mprotect=yes
+fi
+
 ############## platform tests ################
 
 # for flags we don't want to use in config tests:
@@ -4047,6 +4054,7 @@ case "$host_os" in
     EXE_SUFFIX=".exe"
     COLLECTS_PATH="collects"
     skip_iconv_check=yes
+    check_for_mprotect=no
 
 cat >>confdefs.h <<\_ACEOF
 #define HAVE_STDINT_H 1
@@ -5531,6 +5539,72 @@ echo "${ECHO_T}$have_libffi" >&6; }
  fi
 fi
 
+if test "${check_for_mprotect}" = "yes" ; then
+   msg="for mmap and mprotect"
+  { echo "$as_me:$LINENO: checking $msg" >&5
+echo $ECHO_N "checking $msg... $ECHO_C" >&6; }
+  if test "$cross_compiling" = yes; then
+  use_mprotect=no
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+  #include <sys/mman.h>
+    #include <fcntl.h>
+     int main() {
+      void *p;
+      p = mmap(0, 2 << 16, PROT_READ | PROT_WRITE, MAP_PRIVATE, open("/dev/zero", O_RDWR), 0);
+      mprotect(p, 2 << 16, PROT_READ | PROT_WRITE | PROT_EXEC);
+      return 0;
+     }
+_ACEOF
+rm -f conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  use_mprotect=yes
+else
+  echo "$as_me: program exited with status $ac_status" >&5
+echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+( exit $ac_status )
+use_mprotect=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
+fi
+
+
+  { echo "$as_me:$LINENO: result: $use_mprotect" >&5
+echo "${ECHO_T}$use_mprotect" >&6; }
+  if test "${use_mprotect}" = "yes" ; then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_MMAP_MPROTECT 1
+_ACEOF
+
+  fi
+fi
+
 if test "${enable_backtrace}" = "yes" ; then
   GC2OPTIONS="$GC2OPTIONS -DMZ_GC_BACKTRACE"
 fi
diff --git a/src/racket/configure.ac b/src/racket/configure.ac
index f6568e5446..10c803f530 100644
--- a/src/racket/configure.ac
+++ b/src/racket/configure.ac
@@ -469,6 +469,13 @@ if test "${enable_shared}" = "yes" ; then
   LIBRACKET_DEP="${LIBRACKET_DEP} libmzgc.la"
 fi
 
+if test "${enable_foreign}" = "yes" ; then
+  check_for_mprotect=yes
+fi
+if test "${enable_jit}" = "yes" ; then
+  check_for_mprotect=yes
+fi
+
 ############## platform tests ################
 
 # for flags we don't want to use in config tests:
@@ -578,6 +585,7 @@ case "$host_os" in
     EXE_SUFFIX=".exe"
     COLLECTS_PATH="collects"
     skip_iconv_check=yes
+    check_for_mprotect=no
     AC_DEFINE(HAVE_STDINT_H,1,[Have stdint.h])
     if `which ${host}-windres > /dev/null` ; then
       WINDRES="${host}-windres"
@@ -976,6 +984,24 @@ if test "${enable_libffi}" = "yes" ; then
  fi
 fi
 
+if test "${check_for_mprotect}" = "yes" ; then
+  [ msg="for mmap and mprotect" ]
+  AC_MSG_CHECKING($msg)
+  AC_TRY_RUN(
+  [  #include <sys/mman.h> ]
+  [  #include <fcntl.h> ]
+     int main() {
+      void *p;
+      p = mmap(0, 2 << 16, PROT_READ | PROT_WRITE, MAP_PRIVATE, open("/dev/zero", O_RDWR), 0);
+      mprotect(p, 2 << 16, PROT_READ | PROT_WRITE | PROT_EXEC);
+      return 0;
+     }, use_mprotect=yes, use_mprotect=no, use_mprotect=no)
+  AC_MSG_RESULT($use_mprotect)
+  if test "${use_mprotect}" = "yes" ; then
+     AC_DEFINE(HAVE_MMAP_MPROTECT,1,[Have mmap and mprotect])
+  fi
+fi
+
 if test "${enable_backtrace}" = "yes" ; then
   GC2OPTIONS="$GC2OPTIONS -DMZ_GC_BACKTRACE"
 fi
diff --git a/src/racket/mzconfig.h.in b/src/racket/mzconfig.h.in
index 68993db32a..37ffa88cf0 100644
--- a/src/racket/mzconfig.h.in
+++ b/src/racket/mzconfig.h.in
@@ -61,6 +61,9 @@ typedef unsigned long uintptr_t;
 #undef HAVE_EPOLL_SYSCALL
 #undef HAVE_KQUEUE_SYSCALL
 
+/* When mmap() and mprotect() are available: */
+#undef HAVE_MMAP_MPROTECT
+
 /* Enable futures: */
 #undef MZ_USE_FUTURES
 
diff --git a/src/racket/src/salloc.c b/src/racket/src/salloc.c
index 6f22193cfe..d896caab21 100644
--- a/src/racket/src/salloc.c
+++ b/src/racket/src/salloc.c
@@ -39,7 +39,11 @@
 # define MALLOC malloc
 #endif
 
-#ifdef MZ_JIT_USE_MPROTECT
+#if defined(MZ_JIT_USE_MPROTECT) || defined(HAVE_MMAP_MPROTECT)
+# define MZ_CODE_ALLOC_USE_MPROTECT
+#endif
+
+#ifdef MZ_CODE_ALLOC_USE_MPROTECT
 # include <unistd.h>
 # include <sys/mman.h>
 # ifndef MAP_ANON
@@ -851,14 +855,14 @@ THREAD_LOCAL_DECL(static void *code_allocation_page_list);
 
 THREAD_LOCAL_DECL(intptr_t scheme_code_page_total);
 
-#if defined(MZ_JIT_USE_MPROTECT) && !defined(MAP_ANON)
+#if defined(MZ_CODE_ALLOC_USE_MPROTECT) && !defined(MAP_ANON)
 static int fd, fd_created;
 #endif
 
 #define LOG_CODE_MALLOC(lvl, s) /* if (lvl > 1) s */
 #define CODE_PAGE_OF(p) ((void *)(((uintptr_t)p) & ~(page_size - 1)))
 
-#if defined(MZ_JIT_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
+#if defined(MZ_CODE_ALLOC_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
 
 struct free_list_entry {
   intptr_t size; /* size of elements in this bucket */
@@ -1030,7 +1034,7 @@ static intptr_t free_list_find_bucket(intptr_t size)
 
 void *scheme_malloc_code(intptr_t size)
 {
-#if defined(MZ_JIT_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
+#if defined(MZ_CODE_ALLOC_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
 
   intptr_t size2, bucket, sz, page_size;
   void *p, *pg, *prev;
@@ -1109,7 +1113,7 @@ void *scheme_malloc_permanent_code(intptr_t size)
 /* allocate code that will never be freed and that can be used
    in multiple places */
 {
-#if defined(MZ_USE_PLACES) && (defined(MZ_JIT_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC))
+#if defined(MZ_USE_PLACES) && (defined(MZ_CODE_ALLOC_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC))
   void *p;
   intptr_t page_size;
 
@@ -1148,7 +1152,7 @@ void *scheme_malloc_permanent_code(intptr_t size)
 
 void scheme_free_code(void *p)
 {
-#if defined(MZ_JIT_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
+#if defined(MZ_CODE_ALLOC_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
   intptr_t size, size2, bucket, page_size;
   int per_page, n;
   void *prev;
@@ -1234,7 +1238,7 @@ void scheme_free_code(void *p)
 
 void scheme_free_all_code(void)
 {
-#if defined(MZ_JIT_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
+#if defined(MZ_CODE_ALLOC_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
   void *p, *next;
   intptr_t page_size;
 
@@ -1260,7 +1264,7 @@ void scheme_free_all_code(void)
    currently takes advantage of that combination, so we support it
    with scheme_malloc_gcable_code() --- but only in CGC mode. */
 
-#if defined(MZ_JIT_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
+#if defined(MZ_CODE_ALLOC_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
 static uintptr_t jit_prev_page = 0, jit_prev_length = 0;
 #endif
 
@@ -1269,7 +1273,7 @@ void *scheme_malloc_gcable_code(intptr_t size)
   void *p;
   p = scheme_malloc(size);
   
-#if defined(MZ_JIT_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
+#if defined(MZ_CODE_ALLOC_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
   {
     /* [This chunk of code moved from our copy of GNU lightning to here.] */
     uintptr_t page, length, page_size;
@@ -1324,7 +1328,7 @@ void *scheme_malloc_gcable_code(intptr_t size)
 
 void scheme_notify_code_gc()
 {
-#if defined(MZ_JIT_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
+#if defined(MZ_CODE_ALLOC_USE_MPROTECT) || defined(MZ_JIT_USE_WINDOWS_VIRTUAL_ALLOC)
   jit_prev_page = 0;
   jit_prev_length = 0;
 #endif