commit 44fe1b8ea284df6bbaef67e246016d104665b2fe
 Author: Kristian Høgsberg <krh@bitplanet.net>
 Date:   Wed Mar 19 14:03:13 2014 -0700

    os: Add a mechanism to prevent creating any listen sockets

    A socket-activated server will receive its listening sockets from the
    parent process and should not create its own sockets.  This patch
    introduces a NoListen flag that can be set by a DDX to prevent
    the server from creating the sockets.  When NoListen is enabled, we
    also disable the server lock checking, since the parent process is
    responsible for checking the lock before picking the display name and
    creating the sockets.
Signed-off-by: Kristian Høgsberg <krh@bitplanet.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Daniel Stone <daniel@fooishbar.org>
Backported-to-NX-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>