Fortran + X11 compilation

["Jose L. Gomez Dans" <j.l.gomez-dans@sheffield.ac.uk>]

Hi!

   I was told to move to Fortran to do some work, so it's not my fault :)))
I don't have anything to do with Fortran!!!! :))) Anyway, I downloaded the
pgplot graphic libraries, and tried compiling an example program.
Apparently, what I have to do is:
g77 -o outfile infile.f -lpgplot -lX11
  The thing seems to work, but ldd complains it can't find the X11
libraries. I don't know what libraries these are, does anyone have a clue?
Thanks!
Jose
-- 
Jose L Gomez Dans			PhD student
					Radar & Communications Group
					Department of Electronic Engineering
					University of Sheffield UK