i18n: only extract comments marked with "TRANSLATORS:"

When extract l10n messages, we use "--add-comments" option to keep
comments right above the l10n messages for references.  But sometimes
irrelevant comments are also extracted.  For example in the following
code block, the comment in line 2 will be extracted as comment for the
l10n message in line 3, but obviously it's wrong.

        { OPTION_CALLBACK, 0, "ignore-removal", &addremove_explicit,
          NULL /* takes no arguments */,
          N_("ignore paths removed in the working tree (same as
          --no-all)"),
          PARSE_OPT_NOARG, ignore_removal_cb },

Since almost all comments for l10n translators are marked with the same
prefix (tag): "TRANSLATORS:", it's safe to only extract comments with
this special tag.  I.E. it's better to call xgettext as:

        xgettext --add-comments=TRANSLATORS: ...

Also tweaks the multi-line comment in "init-db.c", to make it start with
the proper tag, not "* TRANSLATORS:" (which has a star before the tag).

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -2102,7 +2102,7 @@ pdf:
 
 XGETTEXT_FLAGS = \
 	--force-po \
-	--add-comments \
+	--add-comments=TRANSLATORS: \
 	--msgid-bugs-address="Git Mailing List <git@vger.kernel.org>" \
 	--from-code=UTF-8
 XGETTEXT_FLAGS_C = $(XGETTEXT_FLAGS) --language=C \

builtin/init-db.c

@@ -412,11 +412,9 @@ int init_db(const char *template_dir, unsigned int flags)
 	if (!(flags & INIT_DB_QUIET)) {
 		int len = strlen(git_dir);
 
-		/*
-		 * TRANSLATORS: The first '%s' is either "Reinitialized
-		 * existing" or "Initialized empty", the second " shared" or
-		 * "", and the last '%s%s' is the verbatim directory name.
-		 */
+		/* TRANSLATORS: The first '%s' is either "Reinitialized
+		   existing" or "Initialized empty", the second " shared" or
+		   "", and the last '%s%s' is the verbatim directory name. */
 		printf(_("%s%s Git repository in %s%s\n"),
 		       reinit ? _("Reinitialized existing") : _("Initialized empty"),
 		       shared_repository ? _(" shared") : "",