bug#19776: 25.0.50; HTML rendering is very slow

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Dmitry Antipov <dmantipov@yandex.ru>,  monnier@iro.umontreal.ca,
>   stefan@marxist.se,  rms@gnu.org,  19776@debbugs.gnu.org
> Date: Mon, 25 Oct 2021 19:01:28 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Not sure.  Maybe more reliability?  Signals can be lost or blocked.  I
> > hope Dmitry will be able to answer that.
> 
> Yup.

Also, if we are stuck in pselect call with a long timeout, we won't
get around to calling maybe_quit or process_pending_signals, right?