Hi, This patchset enables Wayland support for GDM: launching GDM itself on Wayland and launching Wayland sessions (the former requires the latter). This is my first contribution, so do not hesitate to give any feedback (I also haven't setup `git send-email` yet so this is a manual mail). 1. Enables optional support for launching a Wayland GDM session. 2. Adds a wrapper for Wayland sessions in order to setup the environment, similar to the default `/etc/profile` or `xinitrc`. Best, Josselin Poiret