[PATCH] Make "git diff" work inside relative subdirectories

We always show the diff as an absolute path, but pathnames to diff are
taken relative to the current working directory (and if no pathnames are
given, the default ends up being all of the current working directory).

Note that "../xyz" also works, so you can do

	cd linux/drivers/char
	git diff ../block

and it will generate a diff of the linux/drivers/block changes.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/diff-files.c b/diff-files.c
index 2e6416e..89eb29b 100644
--- a/diff-files.c
+++ b/diff-files.c
@@ -41,12 +41,12 @@
 	diff_change(oldmode, mode, old_sha1, sha1, path, NULL);
 }
 
-int main(int argc, const char **argv)
+int main(int argc, char **argv)
 {
 	static const unsigned char null_sha1[20] = { 0, };
 	const char **pathspec;
-	int entries = read_cache();
-	int i;
+	const char *prefix = setup_git_directory();
+	int entries, i;
 
 	while (1 < argc && argv[1][0] == '-') {
 		if (!strcmp(argv[1], "-p") || !strcmp(argv[1], "-u"))
@@ -95,8 +95,9 @@
 		argv++; argc--;
 	}
 
-	/* Do we have a pathspec? */
-	pathspec = (argc > 1) ? argv + 1 : NULL;
+	/* Find the directory, and set up the pathspec */
+	pathspec = get_pathspec(prefix, argv + 1);
+	entries = read_cache();
 
 	if (find_copies_harder && detect_rename != DIFF_DETECT_COPY)
 		usage(diff_files_usage);