* alloc.c (check_cons_list): Do not define unless GC_CHECK_CONS_LIST.

* lisp.h (check_cons_list): Declare if GC_CHECK_CONS_LIST; this
avoids undefined behavior in theory.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/alloc.c b/src/alloc.c
index d6b64de5af9..1ad8af0d61a 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -2653,17 +2653,17 @@ DEFUN ("cons", Fcons, Scons, 2, 2, 0,
   return val;
 }
 
+#ifdef GC_CHECK_CONS_LIST
 /* Get an error now if there's any junk in the cons free list.  */
 void
 check_cons_list (void)
 {
-#ifdef GC_CHECK_CONS_LIST
   struct Lisp_Cons *tail = cons_free_list;
 
   while (tail)
     tail = tail->u.chain;
-#endif
 }
+#endif
 
 /* Make a list of 1, 2, 3, 4 or 5 specified objects.  */