bug#29661: 27.0.50; emacs crashing on exchange-point-and-mark

[martin rudalics]

> I now get - but maybe this is anticipated:
>
> Connection lost to X server ':0'
> When compiled with GTK, Emacs cannot recover from X disconnects.
> This is a GTK bug: https://bugzilla.gnome.org/show_bug.cgi?id=85715
> For details, see etc/PROBLEMS.

This is the expected behavior.  I now installed the guards to get there
without segfaulting before.

martin