Match ofs/cnt types in diff interface.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/combine-diff.c b/combine-diff.c
index 4657eb4..eb0d757 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -151,7 +151,8 @@
 struct combine_diff_state {
 	struct xdiff_emit_state xm;
 
-	unsigned int lno, ob, on, nb, nn;
+	unsigned int lno;
+	int ob, on, nb, nn;
 	unsigned long nmask;
 	int num_parent;
 	int n;