anchor.diff:  
   # TODO: Wayland support
   # TODO: investigate libquvi support: it isn't detected by Waf script!
  +# TODO: investigate lua sockets problem
   # TODO: investigate caca support: it isn't detected by Waf script!
   # TODO: a more systematic way to test this package
  
positive.code: { stdenv, fetchurl, fetchgit, freetype, pkgconfig, freefont_ttf, ffmpeg, libass
  , lua5, perl, libpthreadstubs
  , python3, docutils, which
  , x11Support ? true, libX11 ? null, libXext ? null, mesa ? null, libXxf86vm ? null
  , xineramaSupport ? true, libXinerama ? null
  
negative.code:   };
  
    buildInputs = with stdenv.lib;
      [ waf freetype pkgconfig ffmpeg libass docutils which libpthreadstubs lua5_sockets ]
      ++ optionals x11Support [ libX11 libXext mesa libXxf86vm ]
      ++ optional alsaSupport alsaLib
      ++ optional xvSupport libXv
  