anchor.diff:    ];
   
     buildInputs = [
  -    expat file xdg_utils boost libebml zlib
  +    expat file xdg_utils boost libebml zlib fmt
       libmatroska libogg libvorbis flac cmark
     ] ++ optional  stdenv.isDarwin libiconv
       ++ optionals withGUI [ qtbase qtmultimedia ];
  
positive.code: { stdenv, fetchFromGitLab, pkgconfig, autoconf, automake, libiconv
  , drake, ruby, docbook_xsl, file, xdg_utils, gettext, expat, boost
  , libebml, zlib, libmatroska, libogg, libvorbis, flac, libxslt, cmark
  , withGUI ? true
    , qtbase ? null
    , qtmultimedia ? null
  
negative.code: 
  stdenv.mkDerivation rec {
    name = "mkvtoolnix-${version}";
    version = "31.0.0";
  
    src = fetchFromGitLab {
      owner  = "mbunkus";
      repo   = "mkvtoolnix";
      rev    = "release-${version}";
      sha256 = "1fml374ivzzmac0ixhngj4bdxszcaw5yxdmacpn6ia7pdyvpf5lh";
    };
  
    nativeBuildInputs = [
  