anchor.diff:  assert jackaudioSupport -> jackaudio != null;
   assert amrSupport -> (amrnb != null && amrwb != null);
   assert screenSaverSupport -> libXScrnSaver != null;
  +assert vdpauSupport -> libvdpau != null;
   
   let
   
  
positive.code:     ++ stdenv.lib.optional xvidSupport xvidcore
      ++ stdenv.lib.optional pulseSupport pulseaudio
      ++ stdenv.lib.optional screenSaverSupport libXScrnSaver
      ++ stdenv.lib.optional lameSupport lame;
  
    buildNativeInputs = [ yasm ];
  
  
negative.code: , screenSaverSupport ? true, libXScrnSaver
  , pulseSupport ? false, pulseaudio
  , mesa, pkgconfig, unzip, yasm, freefont_ttf
  , vdpauSupport ? false, libvdpau ? null
  }:
  
  assert alsaSupport -> alsaLib != null;
  