anchor.diff:  assert jackaudioSupport -> jackaudio != null;
   assert amrSupport -> (amrnb != null && amrwb != null);
   assert screenSaverSupport -> libXScrnSaver != null;
  +assert vdpauSupport -> libvdpau != null;
   
   let
   
  
positive.code: in  
  
  stdenv.mkDerivation rec {
    name = "MPlayer-1.0-pre31984";
  
    src = fetchurl {
      url = "http://www.loegria.net/misc/${name}.tar.bz2";
      sha256 = "0mg6kggja113rsvvsk05gk50xl5qwzsms6pmb4ylc99mflh7m9km";
    };
  
    buildInputs =
  
negative.code:     ++ stdenv.lib.optional xvidSupport xvidcore
      ++ stdenv.lib.optional pulseSupport pulseaudio
      ++ stdenv.lib.optional screenSaverSupport libXScrnSaver
      ++ stdenv.lib.optional lameSupport lame
      ++ stdenv.lib.optional vdpauSupport libvdpau;
  
    buildNativeInputs = [ yasm ];
  
  