bug#21380: 25.0.50; GTK-induced segfault when scheduling timer from window-configuration-change-hook

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> I believe the currently preferred solution is to block input and
> atimers while copying the timer lists to local copies.  Are you okay
> with that?

Please forgive my ignorance, but why do atimers have to be blocked in
situations where Lisp code isn't supposed to run?  I don't think we ever
run Lisp inside an atimer, and AFAICT atimers are active in most of the
code where Lisp shouldn't run.