anchor.diff: -{ stdenv, fetchurl, pkgconfig, intltool, flex, bison, autoconf, automake, libtool
  +{ stdenv, fetchurl, pkgconfig, intltool, flex, bison, autoreconfHook
   , python, libxml2Python, file, expat, makedepend
   , libdrm, xorg, wayland, udev, llvm, libffi
  -, libvdpau
  +, libvdpau, libelf
   , enableTextureFloats ? false # Texture floats are patented, see docs/patents.txt
  -, enableR600LlvmCompiler ? true, libelf
   , enableExtraFeatures ? false # not maintained
   }:
   
  
positive.code:     ++ optionals stdenv.isLinux [libdrm]
      ;
    buildInputs = with xorg; [
      autoconf automake libtool intltool expat libxml2Python llvm
      libXfixes glproto dri2proto libX11 libXext libxcb libXt
      libffi wayland libvdpau
    ] ++ optionals enableExtraFeatures [ /*libXvMC*/ ]
      ++ optional stdenv.isLinux udev
      ++ optional enableR600LlvmCompiler libelf
      ;
  
    enableParallelBuilding = true;
    #doCheck = true; # https://bugs.freedesktop.org/show_bug.cgi?id=67672
    # TODO: best fix this before merging >=9.2 to master
  
    # move gallium-related stuff to $drivers, so $out doesn't depend on LLVM;
    #   also move libOSMesa to $osmesa, as it's relatively big
  
negative.code:   '';
  
    outputs = ["out" "drivers" "osmesa"];
  
    configureFlags = [
      "--with-dri-driverdir=$(drivers)/lib/dri"
  