anchor.diff:  
     src =  fetchurl {
       url = "ftp://ftp.freedesktop.org/pub/mesa/${version}/MesaLib-${version}.tar.bz2";
  -    sha256 = "0gbacnnacv4x8q27s8my4qhf2xq8q4nyhbs9y9688win4csm12n7";
  +    sha256 = "0p8p35bwvrifc3v4z4wplxrs49h2qwzhcpsfjkkinfckkw6lqvg0";
     };
   
     prePatch = "patchShebangs .";
  
positive.code:       "--enable-osmesa"
        "--enable-openvg" "--enable-gallium-egl" # not needed for EGL in Gallium, but OpenVG might be useful
        #"--enable-xvmc" # tests segfault with 9.1.{1,2,3}
        "--enable-vdpau"
        #"--enable-opencl" # ToDo: opencl seems to need libclc for clover
      ];
  
  
negative.code:     "--enable-gallium-llvm" "--with-llvm-shared-libs"
      "--enable-xa" # used in vmware driver
      "--enable-gles1" "--enable-gles2"
      "--enable-vdpau"
  
      "--with-dri-drivers=i965,r200,radeon"
      ("--with-gallium-drivers=i915,nouveau,r300,r600,svga,swrast"
  