[ns] Problem compiling nam 1.12 & 1.13

[Thomas Seabrooks]

Hi,

    I am having trouble installing nam. When compiling I get the error:
         /usr/bin/ld: skipping incompatible                     
         /usr/X11R6/lib/libX11.sowhen searching for -lX11
         /usr/bin/ld: skipping incompatible                     
        /usr/X11R6/lib/libX11.awhen searching for -lX11
         /usr/bin/ld: cannot find -lX11
            collect2: ld returned 1 exit status
            make: *** [nam] Error 1

I am not sure what this error means or how to fix it. Any advice would
help. I'm using the 2.29 allinone package which comes with nam-1.12. The 
  system has a Xeon 2.8 Ghz and is Running Redhat.

thanks,
Thomas Seabrooks