Index: /trunk/source/lisp-kernel/gc-common.c
===================================================================
--- /trunk/source/lisp-kernel/gc-common.c	(revision 8472)
+++ /trunk/source/lisp-kernel/gc-common.c	(revision 8473)
@@ -815,8 +815,11 @@
 forward_gcable_ptrs()
 {
-  LispObj *prev = &(lisp_global(GCABLE_POINTERS)), next;
+  LispObj *prev = &(lisp_global(GCABLE_POINTERS)), next, new;
 
   while ((next = *prev) != (LispObj)NULL) {
-    *prev = node_forwarding_address(next);
+    new = node_forwarding_address(next);
+    if (new != next) {
+      *prev = new;
+    }
     prev = &(((xmacptr *)ptr_from_lispobj(untag(next)))->link);
   }