Problems in installing Xgraph-12.1

[Chan Kwang Mien <Kwang-Mien.Chan.GP@icn.siemens.de>]

   Hi there,
 
       does anyone have any problem installing the xgraph-12.1 ? i run
´configure´ and it was successful. however, when i run ´make´, the following
error message appears.

         /usr/i486-linux/bin/ld : cannot open -lX11 : 
         No such file or directory
         collect 2 : ld returned 1 exit status
         make : *** [xgraph] Error 1

      can someone enlighten me on this ? I am using Linux SuSe 6.3.

     thanks.

rgds,
kwang mien