[PATCH] Diff-helper update

This patch adds a framework and a stub implementation of rename
detection to diff-helper program.

The current stub code is just enough to detect pure renames in
diff-tree output and not fancier.  The plan is perhaps to use
the same delta code when Nico's delta storage patch is merged
for similarity evaluation purposes.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff.h

@@ -31,7 +31,7 @@ struct diff_spec {
 	unsigned file_valid : 1; /* if false the file does not even exist */
 };
 
-extern void run_external_diff(const char *name,
+extern void run_external_diff(const char *name, const char *other,
 			      struct diff_spec *, struct diff_spec *);
 
 #endif /* DIFF_H */