(digest_single_submenu): Declare all args.

(digest_single_submenu): Declare all args.

Sync with 2002-12-23  Richard M. Stallman  <rms@gnu.org>
changes in xmenu.c:

(parse_single_submenu): Use individual keymap's prompt
string as pane name, if there is one.
(set_frame_menubar): Save menu_items_n_panes from each call to
parse_single_submenu and use it when calling digest_single_submenu.