bug#23368: 25.0.92; xftfont.c has got a bug

[Eli Zaretskii]

> From: handa <handa@gnu.org>
> Cc: nomiya@galaxy.dti.ne.jp, 23368@debbugs.gnu.org
> Date: Mon, 09 May 2016 23:45:11 +0900
> 
> > > CC'ing Handa-san.  This seems to be a duplicate of bug#23360.  Can you
> > > tell which font(s) are used by Wanderlust when this happens?
> 
> I re-read the latest xftfont_open of xftfont.c, but couldn't find a
> problem.  And, as I'm not using Wanderlust, I couldn't reproduce the
> problem.
> 
> Could someone please find a way to reproduce the problem on GNU/Linux
> system by Emacs started with -Q.

Since we want to release Emacs 25.1 soon, I've added a variable,
xft-font-ascent-descent-override, that allows to work around the
problems reported in this and related bugs.  By default, the variable
is nil, which disables overriding the font ascent and descent values,
as this seems to be unnecessary on most systems, and produces annoying
results with some fonts.  On those systems where the override is still
needed, users can set the variable to a non-nil value to solve the
rendering problems.

With that, I consider the bug fixed for Emacs 25.1, and I'm removing
it from the list of bugs that block the release.

We would still want to find a proper fix for these problems, when
their cause becomes known.

Thanks.