Alan Coopersmith authored Oct 07, 2021 and Ray Strode committed Dec 22, 2021

Xorg since version 1.17 doesn't listen to tcp sockets by default
unless it's explicitly built with -Dlisten_tcp=true.

GDM currently assumes X servers 1.17 and later are always built
without specifying -Dlisten_tcp=true and doesn't work properly
otherwise.

This commit enhances GDM to better handle these non-standard builds by
always passing '-nolisten tcp' on the command line when tcp should
be disabled, and likewise always passing '-listen tcp' on the command
line, assuming the X server is new enough to support it, when tcp
should be enabled.

Related #704