Compile X module witout configure finding X libs

[L. Armstrong]

Hey all.  Just thought I'd point out that the setup GUI will let you
(try) to compile the X11 module even if configure didn't find the
necessary files.  It will later dump on you when "Building mol" from:

/usr/bin/ld: cannot find -lX11
(not _exact_ line, there was some stuff before it)

If you want X11 in (as I did) you need to add xlibs-dev (Debian).  I
also added xlibs-pic to be sure, but that may have been overkill

--me

(I'm not a list subscriber)