The first half of this (/var/run/xdm-pid) is already present in -current
   xsrc.  I agree with the second half, but am not sure what location of
   DisplayManager.authDir should be used.  I am CC'ing tech-userlevel on
   this, to see what people think.


/var/X11/xdm is where i've put it previously.


but as the information is useless after a reboot (remote connections
will have died, right?), i don't see why it can't live in, eg,
/var/run/X11/xdm or some other subdir of /var/run.


but i'm not fussed really.