anchor.diff:  , faacSupport ? false, faac ? null
   , dc1394Support ? false, libdc1394 ? null
   , x11grabSupport ? false, libXext ? null, libXfixes ? null
  +, playSupport ? true, SDL ? null
   }:
   
   assert speexSupport -> speex != null;
  
positive.code:     "--enable-gpl"
      "--enable-postproc"
      "--enable-swscale"
      "--disable-ffplay"
      "--enable-shared"
      "--enable-avresample"
      "--enable-runtime-cpudetect"
  
negative.code: assert vaapiSupport -> libva != null;
  assert faacSupport -> faac != null;
  assert x11grabSupport -> libXext != null && libXfixes != null;
  assert playSupport -> SDL != null;
  
  stdenv.mkDerivation rec {
    name = "ffmpeg-1.1.3";
  