Or make sure you have the following in xorg.conf:
Not sure why the $X11BASE/lib/xorg/modules -> $X11BASE/lib/modules maybe xorg R6? Been a while since ran R6.
The move $X11BASE (/usr/X11R6) -> $LOCALBASE (/usr/local) is almost done I believe. I'm running R7.2rc3 with X11BASE=/usr/local in make.conf for quite some time now. The directory /usr/X11R6 doesn't even exist on my systems