diff --git a/diff.h b/diff.h
index 2b6dc0c..729cd02 100644
--- a/diff.h
+++ b/diff.h
@@ -57,6 +57,7 @@
 	int rename_limit;
 	int setup;
 	int abbrev;
+	const char *msg_sep;
 	const char *stat_sep;
 	long xdl_opts;