bug#22976: 24.5; setting unread-command-events to non cons puts emacs in 100% CPU use

[Eli Zaretskii]

> From: Andreas Schwab <schwab@suse.de>
> Date: Thu, 10 Mar 2016 10:42:53 +0100
> Cc: 22976@debbugs.gnu.org
> 
> Eyal Lotem <eyal.lotem@gmail.com> writes:
> 
> > As can be reproduced easily:
> >
> > (setq unread-command-events 1) -- emacs now at 100% CPU
> > (setq unread-command-events nil) -- emacs OK again
> 
> Don't do that then.

Can unread-command-events be anything but nil or a cons cell?  If not,
we could change the few tests of the value to explicitly ignore
non-nil, non-cons values.  Do you see any immediate problems with such
a change?

Thanks.