[RFC PATCH xserver] xwayland: make sure client is not gone in sync callback

[Adam Jackson]

On Mon, 2017-03-06 at 09:32 -0500, Olivier Fourdan wrote:

> Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=100040
> Tested-by: Mark B <mark.blakeney at bullet-systems.net>

remote: I: patch #141671 updated using rev 64ca14b85e45b13628396f21d1903e311f92a9e1.
remote: I: 1 patch(es) updated to state Accepted.
To ssh://git.freedesktop.org/git/xorg/xserver
   5c44169..64ca14b  master -> master

- ajax