wlroots as a subproject now yields the xwayland meson option to its
parent. We need to match the type for this to work. This also adds
support for auto mode, where xwayland is used if present but no warning
is given otherwise.
- Update wlr_box includes to util/box.h: the wlroots header has
been moved upstream.
- Subsurface fields have been moved
- Create renderer and allocator, stop using wlr_backend_get_renderer
- Initalize output rendering