Running Xwayland non-rootless and resizing the output would lead to a
crash while trying to update the larger areas of the root window.
Make sure we resize the backing pixmap according to the new output size
to avoid the crash.
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Closes: https://gitlab.freedesktop.org/xorg/xserver/issues/834
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
(cherry picked from commit ce9455b5ee)
44c693f45d