now that XWayland changed to being it's own server binary, rather than a module for X11, there are several obsolete drivers on the AUR which only create confusion. The new XWayland doesn't need patched drivers anymore.
"In the old model, things like modesetting were done in the video driver, unfortunately. In the old model, we simply patched Xorg with a special magical mode to tell video drivers not to do anything too tricky. For instance, the xf86-video-intel driver had a special branch for Xwayland supporthttp://cgit.freedesktop.org/xorg/driver/xf86-video-intel/log/?h=xwayland. For generic hardware support, we wrote a generic, unaccelerated driverhttp://cgit.freedesktop.org/xorg/driver/xf86-video-wayland that stubbed out most of the functions we needed. With the new approach, we don’t need to patch anything at all." 
There is also an orphaned build of the development X server, which tries to build the old deprecated XWayland approach.  You can see this, because it has --enable-wayland instead of the new --enable-xwayland. Another build is a duplicated of the defacto standard xwayland package (xwayland-git) the difference is that it not only builds XWayland, but also the whole X11 server from the development branch even though this is not needed. People could just use the xorg-server-dev and install xwayland-git and get the same thing.
 https://aur.archlinux.org/packages/xf86-video-ati-xwayland-git/ - Orphaned  https://aur.archlinux.org/packages/xf86-video-intel-xwayland-git/ - Maintained by plfiorinihttps://aur.archlinux.org/packages/?K=plfiorini&SeB=m  https://aur.archlinux.org/packages/xf86-video-wlglamor-git/ - Orphaned  http://blog.mecheye.net/2014/04/xwayland/  https://aur.archlinux.org/packages/xorg-server-xwayland/ - Orphaned  https://aur.archlinux.org/packages/xorg-server-xwayland-dev / - Maintained by maxi_jachttps://aur.archlinux.org/packages/?K=maxi_jac&SeB=m