Add elogind support

Adds support for elogind (standalone variant of systemd-logind)

This wants a corresponding change to xorg/lib/libxtrans, otherwise fd passing isn't going to work:

https://gitlab.freedesktop.org/xorg/lib/libxtrans/blob/master/Xtrans.c#L53

Correct, and this also did not account for libsystemd and elogind on the same system and assumed if elogind was present. I do not, however see a need to separate the checks for elogind as is done for systemd (accounts for the case when this was not in libsystemd). I apologize for jumping the gun on this. I'm closing this request, new one for here and for xtrans to be added.

closed