bug#60580: 29.0.60; crash in xdisp.c with modus theme and display-fill-column-indicator

[Eli Zaretskii]

> Cc: 60580@debbugs.gnu.org
> Date: Thu, 05 Jan 2023 21:57:39 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > From: chad <yandros@gmail.com>
> > Date: Thu, 5 Jan 2023 14:19:48 -0500
> > 
> > From emacs -q, evaluate:
> > 
> >   (custom-set-variables '(custom-enabled-themes '(modus-vivendi)))
> >   (global-display-fill-column-indicator-mode 1)
> > 
> > Emacs will fail the eassert in append_stretch_glyph at
> > xdisp.c:30993.
> 
> Doesn't happen here.  What is your default face's font with that theme?

I guess the culprit is this bit:

  ;;;;; display-fill-column-indicator-mode
      `(fill-column-indicator ((,class :height 1 :background ,bg-region 
:foreground ,bg-region)))

I have no idea what is ":height 1" about, but I think it's wrong and
should be replaced with some reasonable value.