Start Xwayland on demand
Some issues still to iron out... but it's about time to start proposing this. This branch makes it possible to gnome-shell to start without requiring Xwayland upfront, and allow it to be launched when there are other X11 clients that actually require it.
This is at the moment hidden by an experimental gsettings key, and obviously disabled by default. So far the main sore points are:
- https://gitlab.freedesktop.org/xorg/xserver/merge_requests/203 to fix a race condition between a x11 client showing up and mutter setting itself up as a compositor
- https://gitlab.freedesktop.org/xorg/xserver/merge_requests/236 to allow additional clients to be started up with Xwayland (eg. xrdb)
- https://gitlab.freedesktop.org/pulseaudio/pulseaudio/merge_requests/109 so pulseaudio doesn't unintendedly start up Xwayland (incl. deadlock if that first PA client is gnome-shell, and of course it is)
And others. However, the mutter side seems pretty much there, and doesn't hurt to have as it's quite clear this is an experimental feature.