(current_popup_menu, get_menu_item_info):

(current_popup_menu, get_menu_item_info):
(set_menu_item_info): New vars.
(set_frame_menubar): Doc fix clarifying GC interaction with menus.
(w32_menu_show): Set current_popup_menu.
(add_menu_item): Allocate new strings for owner-drawn menu items
and help strings.
Use owner-draw for disabled menu items again.
(w32_menu_display_help): Ignore owner-drawn items and popup menus.
(w32_free_submenu_strings, w32_free_menu_strings): New functions.