[PATCH] Unify usage strings declaration

All usage strings are now declared as static const char [].

This is carried over from my old git-pb branch.

Signed-off-by: Petr Baudis <pasky@ucw.cz>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff-files.c

@@ -6,7 +6,7 @@
 #include "cache.h"
 #include "diff.h"
 
-static const char *diff_files_usage =
+static const char diff_files_usage[] =
 "git-diff-files [-q] "
 "[<common diff options>] [<path>...]"
 COMMON_DIFF_OPTIONS_HELP;