anchor.diff:  , shoutSupport ? true, libshout
   , sqliteSupport ? true, sqlite
   , curlSupport ? true, curl
  -, soupSupport ? true, libsoup
   , audiofileSupport ? true, audiofile
   , bzip2Support ? true, bzip2
  -, ffadoSupport ? true, ffado
   , ffmpegSupport ? true, ffmpeg
   , fluidsynthSupport ? true, fluidsynth
   , zipSupport ? true, zziplib
  
positive.code:     ++ opt shoutSupport libshout
      ++ opt sqliteSupport sqlite
      ++ opt curlSupport curl
      ++ opt soupSupport libsoup
      ++ opt bzip2Support bzip2
      ++ opt audiofileSupport audiofile
      ++ opt (!stdenv.isDarwin && ffadoSupport) ffado
      ++ opt ffmpegSupport ffmpeg
      ++ opt fluidsynthSupport fluidsynth
      ++ opt samplerateSupport libsamplerate
  
negative.code:       (mkFlag aacSupport "aac")
        (mkFlag pulseaudioSupport "pulse")
        (mkFlag stdenv.isDarwin "osx")
        "--enable-debug"
      ]
      ++ opt stdenv.isLinux
        "--with-systemdsystemunitdir=$(out)/etc/systemd/system";
  
  