OTD requires WAYLAND_DISPLAY or DISPLAY to be set,
otherwise it assumes x11 which, on a WAYLAND display configuration,
leads to segfaults on OTD start up. Enforce an ordering
so that we wait until the session has initted before doing
anything.
Upstream has both a check for these environment variables,
as well as enforces a RestartSec=3 to prevent immediate
restarts.
Additionally, it's theoretically possible for DISPLAY to
be set before WAYLAND_DISPLAY, causing segmentation faults
on wayland set ups, so add an explicit polling condition for
that in the ExecStartPre script.
CrystalSplitter
69a7ab07fc