bug#57434: 28.1.91; Terminal Emacs Mac OS flickering.

[Eli Zaretskii]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: kuragin@google.com,  57434@debbugs.gnu.org
> Date: Tue, 30 Aug 2022 14:15:30 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > And if you do
> >
> >   M-: (setq display-line-numbers 'relative) RET
> >
> > does anything change then?
> 
> Nope.
> 
> And it also doesn't flicker with a black terminal bg and starting Emacs
> with -bg <something>.  And it doesn't flicker in the same terminal when
> I start Emacs normally, but set-face-background to something.

OK, thanks.  So now the question of what's different on Dmitrii's
machine is the most relevant one.