anchor.diff:      ++ stdenv.lib.optional xvidSupport xvidcore
       ++ stdenv.lib.optional vdpauSupport libvdpau
       ++ stdenv.lib.optional faacSupport faac
  -    ++ stdenv.lib.optional dc1394Support libdc1394
  -    ++ stdenv.lib.optionals x11grabSupport [ libXext libXfixes ];
  +    ++ stdenv.lib.optional dc1394Support libdc1394;
   
     enableParallelBuilding = true;
       
  
positive.code: , vdpauSupport ? true, libvdpau ? null
  , faacSupport ? false, faac ? null
  , dc1394Support ? false, libdc1394 ? null
  , x11grabSupport ? false, libXext ? null, libXfixes ? null
  }:
  
  assert speexSupport -> speex != null;
  
negative.code: assert xvidSupport -> xvidcore != null;
  assert vdpauSupport -> libvdpau != null;
  assert faacSupport -> faac != null;
  
  stdenv.mkDerivation rec {
    name = "ffmpeg-0.11.1";
  