anchor.diff:  , pkgconfig, intltool, autoreconfHook
   , file, expat, libdrm, xorg, wayland, wayland-protocols, openssl
   , llvmPackages, libffi, libomxil-bellagio, libva-minimal
  -, libelf, libvdpau, valgrind-light, python2
  +, libelf, libvdpau, valgrind-light, python2, python2Packages
   , libglvnd
   , enableRadv ? true
   , galliumDrivers ? null
  
positive.code:     libX11 libXext libxcb libXt libXfixes libxshmfence libXrandr
      libffi libvdpau libelf libXvMC
      libpthreadstubs openssl /*or another sha1 provider*/
      python2 python2.pkgs.Mako
    ] ++ lib.optionals (elem "wayland" eglPlatforms) [ wayland wayland-protocols ]
      ++ lib.optionals stdenv.isLinux [ valgrind-light libomxil-bellagio libva-minimal ];
  
  
negative.code:     "--disable-opencl"
    ];
  
    nativeBuildInputs = [
      autoreconfHook intltool pkgconfig file
      python2 python2Packages.Mako
    ];
  
    propagatedBuildInputs = with xorg; [
      libXdamage libXxf86vm
    ] ++ optional stdenv.isLinux libdrm
      ++ optionals stdenv.isDarwin [ OpenGL Xplugin ];
  
    buildInputs = with xorg; [
  