diff --git a/src/alloc.c b/src/alloc.c
index 1ce32950da3..33c4a1578f3 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -1492,7 +1492,9 @@ struct catchtag
     Lisp_Object tag;
     Lisp_Object val;
     struct catchtag *next;
-/*    jmp_buf jmp;  /* We don't need this for GC purposes */
+#if 0 /* We don't need this for GC purposes */
+    jmp_buf jmp;
+#endif
   };
 
 struct backtrace