This program runs an X server after sanity-checking the environment
and any options passed to it.  It is meant to enhance security on
multi-user systems running XFree86 4 or the X11 server from x.org,
where the ability to use a startx script is needed.  If you have
XFree86 3, do not install this:  you do not need it and it will not
work.  If you have no untrusted users or always run the X server
from xdm, you do not need this.