(popup-menu): Run the keymap through indirect-function,

(popup-menu): Run the keymap through indirect-function,
in case it was defined with define-prefix-key.  If the menu is a
list of keymaps, look up the binding of user's choice in each one
of the keymaps.
(mouse-popup-menubar): If the global and local menu-bar keymaps
don't have a prompt string, create one and insert it into the
keymap.  Don't barf if current-local-map returns nil.