diff --git a/src/mzscheme/gc2/compact.c b/src/mzscheme/gc2/compact.c
index 758207dde0..ea193991c3 100644
--- a/src/mzscheme/gc2/compact.c
+++ b/src/mzscheme/gc2/compact.c
@@ -495,6 +495,9 @@ void GC_register_traversers(Type_Tag tag, Size_Proc size, Mark_Proc mark, Fixup_
 void GC_register_thread(void *p, void *c)
 {
 }
+void GC_register_new_thread(void *p, void *c)
+{
+}
 
 /******************************************************************************/
 /*                             immobile box                                   */
diff --git a/src/mzscheme/gc2/gc2.h b/src/mzscheme/gc2/gc2.h
index 59b94280b2..460bab0531 100644
--- a/src/mzscheme/gc2/gc2.h
+++ b/src/mzscheme/gc2/gc2.h
@@ -73,10 +73,13 @@ GC2_EXTERN void GC_init_type_tags(int count, int weakbox, int ephemeron);
    freedom in the layout of a weak box or ephemeron, so it performs weak
    box traversals itself, but MzScheme gets to choose the tag.) */
 
-GC2_EXTERN void GC_register_thread(void *, void *);
+GC2_EXTERN void GC_register_new_thread(void *, void *);
 /*
    Indicates that a just-allocated point is for a thread record
    owned by a particular custodian. */
+GC2_EXTERN void GC_register_thread(void *, void *);
+/*
+   Indicates that a a thread record is owned by a particular custodian. */
 
 GC2_EXTERN void (*GC_collect_start_callback)(void);
 GC2_EXTERN void (*GC_collect_end_callback)(void);
diff --git a/src/mzscheme/gc2/newgc.c b/src/mzscheme/gc2/newgc.c
index 536863f075..9e8d7795de 100644
--- a/src/mzscheme/gc2/newgc.c
+++ b/src/mzscheme/gc2/newgc.c
@@ -1052,6 +1052,16 @@ struct thread {
 static Mark_Proc normal_thread_mark = NULL, normal_custodian_mark = NULL;
 static struct thread *threads = NULL;
 
+inline static void register_new_thread(void *t, void *c)
+{
+  struct thread *work;
+
+  work = (struct thread *)malloc(sizeof(struct thread));
+  work->owner = current_owner((Scheme_Custodian *)c);
+  work->thread = t;
+  work->next = threads;
+  threads = work;
+}
 inline static void register_thread(void *t, void *c)
 {
   struct thread *work;
@@ -1061,11 +1071,7 @@ inline static void register_thread(void *t, void *c)
       work->owner = current_owner((Scheme_Custodian *)c);
       return;
     }
-  work = (struct thread *)malloc(sizeof(struct thread));
-  work->owner = current_owner((Scheme_Custodian *)c);
-  work->thread = t;
-  work->next = threads;
-  threads = work;
+  register_new_thread(t, c);
 }
 
 inline static void mark_threads(int owner)
@@ -1110,6 +1116,7 @@ inline static int thread_get_owner(void *p)
 
 #ifndef NEWGC_BTC_ACCOUNT
 # define register_thread(t,c) /* */
+# define register_new_thread(t,c) /* */
 # define clean_up_thread_list() /* */
 #endif
 
@@ -1117,6 +1124,10 @@ void GC_register_thread(void *t, void *c)
 {
   register_thread(t, c);
 }
+void GC_register_new_thread(void *t, void *c)
+{
+  register_new_thread(t, c);
+}
 
 /*****************************************************************************/
 /* Internal Stack Routines                                                   */
diff --git a/src/mzscheme/src/thread.c b/src/mzscheme/src/thread.c
index 88203ce800..c93efc7fbe 100644
--- a/src/mzscheme/src/thread.c
+++ b/src/mzscheme/src/thread.c
@@ -1943,7 +1943,7 @@ static Scheme_Thread *make_thread(Scheme_Config *config,
     mgr = (Scheme_Custodian *)scheme_get_param(config, MZCONFIG_CUSTODIAN);
 
 #ifdef MZ_PRECISE_GC
-  GC_register_thread(process, mgr);
+  GC_register_new_thread(process, mgr);
 #endif
 
   {
@@ -2820,7 +2820,7 @@ static Scheme_Object *call_as_nested_thread(int argc, Scheme_Object *argv[])
   np = MALLOC_ONE_TAGGED(Scheme_Thread);
   np->so.type = scheme_thread_type;
 #ifdef MZ_PRECISE_GC
-  GC_register_thread(np, mgr);
+  GC_register_new_thread(np, mgr);
 #endif
   np->running = MZTHREAD_RUNNING;
   np->ran_some = 1;