[ncl-install] problems with 5.1.1 binary distribution on RHEL4

[Gary Klaassen]

Hi, I've installed ncl_ncarg-5.1.1.Linux_x86_64_gcc412.tar.gz on an RHEL4 
64-bit system with that version of gcc. It was untarred into /usr/local/ncarg 
and the necessary environment variables are set.

The first thing I noticed is that there is no /usr/local/ncarg/man,
i.e. all the usual man pages are missing.

The following works as expected:
   ng4ex gsun01n; ncl gsun01n.ncl

However,  ncargex cpex08 generates:

  Compiling and linking...
  gfortran -fPIC -fno-second-underscore -fno-range-check -O -o cpex08
    cpexcc.f cpex08.f -L/usr/local/ncarg/lib -lncarg -lncarg_gks -lncarg_c
    -lX11 -lXext -lpng -lz
  /usr/bin/ld: cannot find -lX11
  collect2: ld returned 1 exit status

  The compile and link failed.

I have both xorg-x11 and xorg-x11-devel installed.

Any help would be appreciated. thanks, Gary Klaassen, York University