bug#58406: 29.0.50; Bars refactoring?

[Eli Zaretskii]

> Cc: 58406@debbugs.gnu.org
> From: Manuel Giraud <manuel@ledu-giraud.fr>
> Date: Mon, 10 Oct 2022 16:30:00 +0200
> 
> I understand that all of this takes place in the "--with-x-toolkit=no"
> land and that it might not be the most used setup but maybe it could be
> a place to test some moderately "wild" ideas 😊

The same code is used by menus on TTY frames and by the MSDOS build,
FWIW.