XSERVER_DTRACE needs request names from registry too

The dtrace code in the server wants to log the name of each executed
request, which it gets from the registry. Use that as an additional
indication of when that portion of the registry should be included in
the server build.

See:

http://tinderbox.x.org/builds/2014-09-19-0003/logs/xserver/#build

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Dave Airlie <airlied@gmail.com>
Require xtrans 1.3.5 or newer

This version of xtrans offers the TRANS(Listen) function.

Signed-off-by: Keith Packard <keithp@keithp.com>
os: Don't listen to 'tcp' by default. Add '-listen' option. [v2]

This disables the tcp listen socket by default. Then, it
uses a new xtrans interface, TRANS(Listen), to provide a command line
option to re-enable those if desired.

v2: Leave unix socket enabled by default. Add configure options.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>