bug#24634: 25.1 on Windows (native and cygwin+w32): high CPU load with "wavy" characters

[Eli Zaretskii]

> From: Georges Ko <gko@gko.net>
> Date: Sat, 08 Oct 2016 23:24:24 +0800
> 
> > static void
> > compact_font_caches (void)
> > {
> >   struct terminal *t;
> >
> >   for (t = terminal_list; t; t = t->next_terminal)
> >     {
> >       Lisp_Object cache = TERMINAL_FONT_CACHE (t);
> >       mark_object (cache);
> >     }
> > }
> 
> OK, this version fixes all cases!

OK, I've now added a variable which you can set to non-nil to disable
font cache compaction.  See the latest emacs-25 branch.

Thanks.