Add utf8_fprintf helper that returns correct number of columns

Since command usages can be translated, they may include utf-8
encoded strings, and the output in console may not align well any
more. This is because strlen() is different from strwidth() on utf-8
strings.

A wrapper utf8_fprintf() can help to return the correct number of
columns required.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Reviewed-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/parse-options.c b/parse-options.c
index c1c66bd..670bf09 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -3,6 +3,7 @@
 #include "cache.h"
 #include "commit.h"
 #include "color.h"
+#include "utf8.h"
 
 static int parse_options_usage(struct parse_opt_ctx_t *ctx,
 			       const char * const *usagestr,
@@ -491,7 +492,7 @@
 			s = literal ? "[%s]" : "[<%s>]";
 	else
 		s = literal ? " %s" : " <%s>";
-	return fprintf(outfile, s, opts->argh ? _(opts->argh) : _("..."));
+	return utf8_fprintf(outfile, s, opts->argh ? _(opts->argh) : _("..."));
 }
 
 #define USAGE_OPTS_WIDTH 24
@@ -550,7 +551,7 @@
 		if (opts->long_name)
 			pos += fprintf(outfile, "--%s", opts->long_name);
 		if (opts->type == OPTION_NUMBER)
-			pos += fprintf(outfile, "-NUM");
+			pos += utf8_fprintf(outfile, _("-NUM"));
 
 		if ((opts->flags & PARSE_OPT_LITERAL_ARGHELP) ||
 		    !(opts->flags & PARSE_OPT_NOARG))