I've RTFMed and I get the following error while compiling:

gcc -g -O2 -rdynamic  main.o ext/extinit.o ext/curses/curses.a
ext/etc/etc.a ext/fcntl/fcntl.a ext/md5/md5.a ext/pty/pty.a
ext/sdbm/sdbm.a ext/socket/socket.a ext/tcltklib/tcltklib.a
ext/tk/tkutil.a  libruby.a -ldl -lcrypt -lm  libruby.a -lncurses -lc
-lgdbm -lc libruby.a -lc libruby.a -lc libruby.a -lc libruby.a -lc
libruby.a -lc libruby.a -lc libruby.a -ltk -ltcl -lX11 -lm -ldl -lc
libruby.a -lc -o ruby
/usr/bin/ld: cannot find -lX11
collect2: ld returned 1 exit status
make[1]: *** [ruby] Error 1

I'm really excited about using Ruby... therefore any help and/or
suggestions will be much appreciated... :)
Mike
THANX