xsu integration, test version

[Timothee Besset]

I have uploaded a test version of xsu integrated with setup. It is based
on setup-1.5.6 from icculus.org and xsu-0.2.2 (http://xsu.freax.eu.org). I
have modified xsu to remove dependencies to gnome libs and static linked
the relevant stuff to make it as binary compatible as possible without
bumping the size too much (it's 234kb as it is already).

http://zerowing.idsoftware.com/loki_setup/

I'd appreciate if you have time to download this and run it on your own
machine, to make sure that the ABI is good.

My changes are living at
http://zerowing.idsoftware.com/viewcvs/viewcvs.cgi/loki_setup until I have
a good and tested solution. The xsu tweaks are in loki_setup/xsu, ABI
branch. 

If you are curious, look at setup.sh changes. If xsu fails for some
reason, or if it's a console installation, it will call /bin/su instead

After you guys have time to review this and we discuss it, I'd like to get
that merged back in the main tree if possible.

TTimo