Don't allow MARKBIT and DONT_COPY_FLAG to be the same bit.

diff --git a/src/alloc.c b/src/alloc.c
index 5776a2be9271076ce8f47ca7e897bfeb8e5c00c8..29e0ab46ea0f26f48e3c0741673ea2bf83ed99ec 100644 (file)
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -118,6 +118,10 @@ Lisp_Object memory_signal_data;
 #define DONT_COPY_FLAG 1
 #endif /* no DONT_COPY_FLAG  */
 
+#if DONT_COPY_FLAG == MARKBIT
+you lose
+#endif
+
 /* Buffer in which we save a copy of the C stack at each GC.  */
 
 char *stack_copy;