bug#21556: 25.0.50; Memory leak in emacs -Q with lucid (font)

[Eli Zaretskii]

> From: Dima Kogan <dima@secretsauce.net>
> Cc: handa@gnu.org, 21556@debbugs.gnu.org, dmantipov@yandex.ru
> Date: Tue, 29 Sep 2015 02:28:56 -0700
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > So, if you prefer not to invest any time in investigating the font
> > marking code, let's wait for Dmitry to respond, and make the decision
> > when he does (or when we give up waiting).
> 
> I guess I preferred to invest more time. I found and fixed the bug, and
> the patch is attached. The issue was that the compaction code wasn't
> checking all the right lisp objects for the marks. The font entities
> were storing a list of fonts, and this list had to be traversed, looking
> for the marks. See font_clear_cache() for a function that WAS traversing
> the full list.

Thanks!

Let's wait for a week for comments, and if nothing significant comes
up, let's install this.