fix const-correctness of write_sha1_file

These should take const buffers as input data, but zlib's
next_in pointer is not const-correct. Let's fix it at the
zlib level, though, so the cast happens in one obvious
place. This should be safe, as a similar cast is used in
zlib's example code for a const array.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/cache.h b/cache.h
index 6dcb100a6c..5eb0573bcc 100644
--- a/cache.h
+++ b/cache.h
@@ -701,7 +701,7 @@ static inline void *read_sha1_file(const unsigned char *sha1, enum object_type *
 	return read_sha1_file_repl(sha1, type, size, NULL);
 }
 extern int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1);
-extern int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
+extern int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 extern int pretend_sha1_file(void *, unsigned long, enum object_type, unsigned char *);
 extern int force_object_loose(const unsigned char *sha1, time_t mtime);