extern int hold_lock_file_for_update(struct lock_file *, const char *path, int);
extern int commit_lock_file(struct lock_file *);
extern void rollback_lock_file(struct lock_file *);
-extern int delete_ref(const char *, unsigned char *sha1);
+extern int delete_ref(const char *, const unsigned char *sha1);
/* Environment bits from configuration mechanism */
extern int use_legacy_headers;