sha1_file: export `git_open_noatime`

The `git_open_noatime` helper can be of general interest for other
consumers of git's different on-disk formats.

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

cache.h

@@ -780,6 +780,7 @@ extern int hash_sha1_file(const void *buf, unsigned long len, const char *type,
 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);
+extern int git_open_noatime(const char *name);
 extern void *map_sha1_file(const unsigned char *sha1, unsigned long *size);
 extern int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz);
 extern int parse_sha1_header(const char *hdr, unsigned long *sizep);

sha1_file.c

@@ -239,8 +239,6 @@ char *sha1_pack_index_name(const unsigned char *sha1)
 struct alternate_object_database *alt_odb_list;
 static struct alternate_object_database **alt_odb_tail;
 
-static int git_open_noatime(const char *name);
-
 /*
  * Prepare alternate object database registry.
  *
@@ -1357,7 +1355,7 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
 	return hashcmp(sha1, real_sha1) ? -1 : 0;
 }
 
-static int git_open_noatime(const char *name)
+int git_open_noatime(const char *name)
 {
 	static int sha1_file_open_flag = O_NOATIME;