+#if defined(SAVE_CALL_CHAIN) && \
+ !(defined(REDIRECT_MALLOC) && defined(GC_HAVE_BUILTIN_BACKTRACE))
+# define SAVE_CALL_CHAIN_IN_GC
+ /* This is only safe if the call chain save mechanism won't end up */
+ /* calling GC_malloc. The GNU C library documentation suggests */
+ /* that backtrace doesn't use malloc, but at least the initial */
+ /* call in some versions does seem to invoke the dynamic linker, */
+ /* which uses malloc. */
+#endif
+