anchor.diff:  , libsm
   , libtiff
   , libx11
  +, libxext
  +, libxcursor
  +, libxft
  +, libxrandr
  +, libxrender
   , opengl-dummy
  -, xorg
  +, xorgproto
   , zlib
   }:
   
  
positive.code:     libsm
      libtiff
      libx11
      opengl-dummy
      xorg.libXext
      xorg.libXcursor
      xorg.libXft
      xorg.libXrandr
      xorg.libXrender
      xorg.renderproto
      xorg.xproto
      zlib
    ];
  
  
negative.code: 
    version = "1.6.54";
  in
  stdenv.mkDerivation rec {
    name = "fox-${version}";
  
  