bug#64270: 30.0.50; Font update for no toolkit menu

[Eli Zaretskii]

> From: Manuel Giraud <manuel@ledu-giraud.fr>
> Cc: 64270@debbugs.gnu.org
> Date: Tue, 27 Jun 2023 09:04:51 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Date: Sat, 24 Jun 2023 19:00:04 +0200
> >> From:  Manuel Giraud via "Bug reports for GNU Emacs,
> >>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> >> 
> >> I'd like to be able to update the menu font (for the no toolkit build)
> >> at runtime.  For this, my idea was to pass the font (from say the menu
> >> face) to the XMenuCreate call in x_menu_show.
> >
> > Doesn' paneFont X resource already allow that?
> 
> Yes it does and I'm using it.  What I'm trying to achieve here is to be
> able to change those menu face dynamically: if a user changes the main
> frame font with 'set-frame-font', the menu font is also changed.

Do you mean that the menu font will change to the same font as the
frame's default face?  If so, I'm not sure that's a good idea: menu
fonts are normally different from the default font, and in particular
menus look nicer with variable-pitch fonts, whereas the default face
should preferably use a fixed-pitch font.

If this is not what you meant, then how would Emacs know which font to
select for menus when the default face's font is changed?