/* handling of delta objects */
struct delta;
struct object_list;
-extern struct delta *lookup_delta(unsigned char *sha1);
+extern struct delta *lookup_delta(const unsigned char *sha1);
extern int parse_delta_buffer(struct delta *item, void *buffer, unsigned long size);
extern int parse_delta(struct delta *item, unsigned char sha1);
extern int process_deltas(void *src, unsigned long src_size,