Merge branch 'skip-gettext-when-possible'

This topic branch allows us to skip the gettext initialization
when the locale directory does not even exist.

This saves 150ms out of 210ms for a simply `git version` call on
Windows, and it most likely will help scripts that call out to
`git.exe` hundreds of times.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Makefile

@@ -445,6 +445,7 @@ lib = lib
 # DESTDIR =
 pathsep = :
 
+localedir_relative = $(patsubst $(prefix)/%,%,$(localedir))
 mandir_relative = $(patsubst $(prefix)/%,%,$(mandir))
 infodir_relative = $(patsubst $(prefix)/%,%,$(infodir))
 htmldir_relative = $(patsubst $(prefix)/%,%,$(htmldir))
@@ -1603,6 +1604,7 @@ bindir_relative_SQ = $(subst ','\'',$(bindir_relative))
 mandir_relative_SQ = $(subst ','\'',$(mandir_relative))
 infodir_relative_SQ = $(subst ','\'',$(infodir_relative))
 localedir_SQ = $(subst ','\'',$(localedir))
+localedir_relative_SQ = $(subst ','\'',$(localedir_relative))
 gitexecdir_SQ = $(subst ','\'',$(gitexecdir))
 template_dir_SQ = $(subst ','\'',$(template_dir))
 htmldir_relative_SQ = $(subst ','\'',$(htmldir_relative))
@@ -2039,7 +2041,7 @@ attr.sp attr.s attr.o: EXTRA_CPPFLAGS = \
 
 gettext.sp gettext.s gettext.o: GIT-PREFIX
 gettext.sp gettext.s gettext.o: EXTRA_CPPFLAGS = \
-	-DGIT_LOCALE_PATH='"$(localedir_SQ)"'
+	-DGIT_LOCALE_PATH='"$(localedir_relative_SQ)"'
 
 http-push.sp http.sp http-walker.sp remote-curl.sp imap-send.sp: SPARSE_FLAGS += \
 	-DCURL_DISABLE_TYPECHECK

common-main.c

@@ -31,10 +31,10 @@ int main(int argc, const char **argv)
 	 */
 	sanitize_stdfds();
 
-	git_setup_gettext();
-
 	git_extract_argv0_path(argv[0]);
 
+	git_setup_gettext();
+
 	restore_sigpipe_to_default();
 
 	return cmd_main(argc, argv);

gettext.c

@@ -6,6 +6,8 @@
 #include "gettext.h"
 #include "strbuf.h"
 #include "utf8.h"
+#include "cache.h"
+#include "exec_cmd.h"
 
 #ifndef NO_GETTEXT
 #	include <locale.h>
@@ -160,14 +162,22 @@ static void init_gettext_charset(const char *domain)
 void git_setup_gettext(void)
 {
 	const char *podir = getenv("GIT_TEXTDOMAINDIR");
+	char *p = NULL;
 
 	if (!podir)
 		podir = GIT_LOCALE_PATH;
-	bindtextdomain("git", podir);
-	setlocale(LC_MESSAGES, "");
-	setlocale(LC_TIME, "");
-	init_gettext_charset("git");
-	textdomain("git");
+	if (!is_absolute_path(podir))
+		podir = p = system_path(podir);
+
+	if (is_directory(podir)) {
+		bindtextdomain("git", podir);
+		setlocale(LC_MESSAGES, "");
+		setlocale(LC_TIME, "");
+		init_gettext_charset("git");
+		textdomain("git");
+	}
+
+	free(p);
 }
 
 /* return the number of columns of string 's' in current locale */