Work around missing hard links on FAT formatted media

FAT -- like Coda -- does not like cross-directory hard links. To be
precise, FAT does not like links at all. But links are not needed either.
So get rid of them.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

clone-pack.c

@@ -211,7 +211,7 @@ static int clone_without_unpack(int fd[2])
 
 	ifd = fd[0];
 	snprintf(tmpfile, sizeof(tmpfile),
-		 "%s/pack-XXXXXX", get_object_directory());
+		 "%s/pack/tmp-XXXXXX", get_object_directory());
 	ofd = mkstemp(tmpfile);
 	if (ofd < 0)
 		return error("unable to create temporary file %s", tmpfile);

sha1_file.c

@@ -1239,11 +1239,14 @@ int move_temp_to_file(const char *tmpfile, char *filename)
 		 * won't be able to check collisions, but that's not a
 		 * big deal.
 		 *
+		 * The same holds for FAT formatted media.
+		 *
 		 * When this succeeds, we just return 0. We have nothing
 		 * left to unlink.
 		 */
-		if (ret == EXDEV && !rename(tmpfile, filename))
+		if ((ret == EXDEV || ret == ENOTSUP) && !rename(tmpfile, filename))
 			return 0;
+		ret = errno;
 	}
 	unlink(tmpfile);
 	if (ret) {