Tell between packed, unpacked and symbolic refs.

This adds a "int *flag" parameter to resolve_ref() and makes
for_each_ref() family to call callback function with an extra
"int flag" parameter.  They are used to give two bits of
information (REF_ISSYMREF and REF_ISPACKED) about the ref.

Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-pack-refs.c

@@ -9,7 +9,8 @@ static void remove_lock_file(void)
 		unlink(lock_path);
 }
 
-static int handle_one_ref(const char *path, const unsigned char *sha1, void *cb_data)
+static int handle_one_ref(const char *path, const unsigned char *sha1,
+			  int flags, void *cb_data)
 {
 	FILE *refs_file = cb_data;