anchor.diff:      ++ stdenv.lib.optional xvidSupport xvidcore
       ++ stdenv.lib.optional vdpauSupport libvdpau
       ++ stdenv.lib.optional faacSupport faac
  -    ++ stdenv.lib.optional dc1394Support libdc1394;
  +    ++ stdenv.lib.optional dc1394Support libdc1394
  +    ++ stdenv.lib.optionals x11grabSupport [ libXext libXfixes ];
   
     enableParallelBuilding = true;
       
  
positive.code: assert xvidSupport -> xvidcore != null;
  assert vdpauSupport -> libvdpau != null;
  assert faacSupport -> faac != null;
  
  stdenv.mkDerivation rec {
    name = "ffmpeg-0.11.1";
  
negative.code:     ++ stdenv.lib.optional xvidSupport "--enable-libxvid"
      ++ stdenv.lib.optional vdpauSupport "--enable-vdpau"
      ++ stdenv.lib.optional faacSupport "--enable-libfaac --enable-nonfree"
      ++ stdenv.lib.optional dc1394Support "--enable-libdc1394"
      ++ stdenv.lib.optional x11grabSupport "--enable-x11grab";
  
    buildInputs = [ pkgconfig lame yasm zlib bzip2 ]
      ++ stdenv.lib.optional mp3Support lame
  