anchor.diff:    
     preBuild = "
       makeFlagsArray=(INSTALL_DIR=$out DRI_DRIVER_INSTALL_DIR=$out/lib/modules/dri SHELL=$SHELL)
  +    cp ${missingPC} src/glw/glw.pc.in
     ";
     
     buildInputs = [
  
positive.code:     if stdenv.system == "x86_64-linux" then "linux-dri-x86-64" else
      abort "unsupported platform for Mesa"; # !!! change to throw, remove all the mesa asserts in all-packages.nix
  
  in
  
  stdenv.mkDerivation {
    name = "mesa-7.0.1";
    
    src = fetchurl {
      url = mirror://sourceforge/mesa3d/MesaLib-7.0.1.tar.bz2;
      md5 = "c056abd763e899114bf745c9eedbf9ad";
    };
  /*    (fetchurl {
        url = http://nix.cs.uu.nl/dist/tarballs/MesaGLUT-6.4.tar.bz2;
  
negative.code:   passthru = {inherit libdrm;};
    
    meta = {
      description = "An open source implementation of OpenGL";
      homepage = http://www.mesa3d.org/;
    };
  }
  