--- a/src/patch.c
+++ b/src/patch.c
@@ -684,7 +684,7 @@
 }
 
 static char const shortopts[] = "bB:cd:D:eEfF:g:i:l"
-#if 0 && defined ENABLE_MERGE
+#if defined ENABLE_MERGE
 				"m"
 #endif
 				"nNo:p:r:RstTuvV:x:Y:z:Z";
