bug#60841: 30.0.50; kill-ring-save pauses despite region being highlighted

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: Eli Zaretskii <eliz@gnu.org>,  gregory@heytings.org,  
> 60841@debbugs.gnu.org
> Date: Sun, 29 Jan 2023 19:55:00 +0200
> 
> > The only place where this "matters" is in replace.el, AFAICT:
> >
> > 1. Customize list-matching-lines-prefix-face to 'default,
> >
> > 2. (face-differs-from-default-p list-matching-lines-prefix-face)
> >    ↦ :stipple
> 
> I still don't understand why (face-differs-from-default-p 'default)
> should return :stipple even in a clean state after emacs -Q.
> This means that the default face always differs from itself?

Because face-differs-from-default-p thinks attributes are unset only
if their value is 'unspecified'.  We should fix that so the function
knows about nil as well.  (:stipple is simply the last attribute in
the list returned by

   (delq :inherit (mapcar 'car face-attribute-name-alist))