bug#56502: Lucid ghosts

[Po Lu]

Alan Mackenzie <acm@muc.de> writes:

> Hello, Emacs.
>
> While checking for Lisp hooks in the display engine, I came across some
> unused variables with "lucid" in their names, namely
> Vlucid_menu_bar_dirty_flag and Qrecompute_lucid_menubar.  These could
> surely now be removed from Emacs, saving a small amount of space and
> execution time.
>
> A grep through the project's sources suggests there are other ghosts with
> "lucid", and these could probably also be removed.

AFAIR those were left over from the original Lucid Emacs menu bar
implementation.  Nobody still uses them, so they can be deleted.