anchor.diff:      (wtFlag "boost" (boost != null) null)
       (wtFlag "boost-libdir" (boost != null) "${boost.lib}/lib")
       "--with-gettext"
  -    "--disable-tools"
  +    "--without-tools"
     ];
   
     buildPhase = ''
  
positive.code: , libmatroska
  , libogg
  , libvorbis
  , qt5
  , xdg-utils
  , zlib
  # pugixml (not packaged)
  }:
  
  with {
  
negative.code:     wtFlag;
  };
  
  assert qt5 != null -> qt5.qtbase != null;
  
  stdenv.mkDerivation rec {
    name = "mkvtoolnix-${version}";
    version = "8.9.0";
  
    src = fetchurl {
      url = "http://www.bunkus.org/videotools/mkvtoolnix/sources/${name}.tar.xz";
      sha256 = "1m50m8lkfpk0663zhhx9alvprf2y6b4lj9wj29xn3a1rjf2b421j";
    };
  
    nativeBuildInputs = [
  