bug#30558: 26.0.90; Emacs crashes XWindows when run with GUI

[Eli Zaretskii]

> From: Lee Hinman <leehinman@fastmail.com>
> From: Lee Hinman <leehinman@fastmail.com>
> Date: Tue, 20 Feb 2018 14:30:41 -0700
> 
> 
> After a recent Fedora system update (updating XWindows and Mesa and
> things) I am no longer able to run Emacs in a GUI. When I run:
> 
> (Emacs compiled from the master branch at the date of this posting)
> $ src/emacs -Q
> 
> And then if I attempt to resize the Emacs window at all, X11 hangs until
> I get booted back to the GDM login screen.
> 
> Here is the output from GDB `bt` (note that this may not be for master,
> it's from the emacs-26 branch because I couldn't get the dump to load
> correctly for the master branch one, but the crash is the same on both
> emacs-26 and master branch):

Looks like a GTK issue to me.