Update makefile in preparation for Documentation/config/*.txt

config.txt is going to be broken down in smaller pieces and put under
Documentation/config directory. Update build rules to take these files
into account.

A dummy file is added to make sure wildcard expansion is predictable
(depending on shell setting it could expand to nothing or becomes a
path if config directory is empty). The file will be deleted once the
move is over.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

generate-cmdlist.sh

@@ -80,7 +80,7 @@ print_config_list () {
 	cat <<EOF
 static const char *config_name_list[] = {
 EOF
-	grep -h '^[a-zA-Z].*\..*::$' Documentation/*config.txt |
+	grep -h '^[a-zA-Z].*\..*::$' Documentation/*config.txt Documentation/config/*.txt |
 	sed '/deprecated/d; s/::$//; s/,  */\n/g' |
 	sort |
 	while read line