i18n: git-tag tag_template message

Mark the tag_template message as translatable with N_() and then use
it later with _(). We need to skip a test under GETTEXT_POISON that
relies on the output having a leading newline.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/tag.c

@@ -213,10 +213,10 @@ static int do_sign(struct strbuf *buffer)
 }
 
 static const char tag_template[] =
-	"\n"
+	N_("\n"
 	"#\n"
 	"# Write a tag message\n"
-	"#\n";
+	"#\n");
 
 static void set_signingkey(const char *value)
 {
@@ -305,7 +305,7 @@ static void create_tag(const unsigned char *object, const char *tag,
 		if (!is_null_sha1(prev))
 			write_tag_body(fd, prev);
 		else
-			write_or_die(fd, tag_template, strlen(tag_template));
+			write_or_die(fd, _(tag_template), strlen(_(tag_template)));
 		close(fd);
 
 		if (launch_editor(path, buf, NULL)) {

t/t7004-tag.sh

@@ -1121,6 +1121,7 @@ test_expect_success \
 '
 
 test_expect_success \
+	C_LOCALE_OUTPUT \
 	'message in editor has initial comment: first line' '
 	# check the first line --- should be empty
 	echo >first.expect &&