anchor.diff:      #(enableFeature (libnut != null) "libnut")
       (enableFeature (libopus != null) "libopus")
       (enableFeature (librsvg != null) "librsvg")
  +    (enableFeature (srt != null) "libsrt")
       (enableFeature (libssh != null) "libssh")
       (enableFeature (libtheora != null) "libtheora")
       (enableFeature (if isLinux then libv4l != null else false) "libv4l2")
  
positive.code: #, shine ? null # Fixed-point MP3 encoder
  , soxr ? null # Resampling via soxr
  , speex ? null # Speex de/encoder
  #, twolame ? null # MP2 encoder
  #, utvideo ? null # Ut Video de/encoder
  , vid-stab ? null # Video stabilization
  
negative.code:     libjack2 ladspaH lame libaom libass libbluray libbs2b libcaca libdc1394 libmodplug libmysofa
      libogg libopus librsvg libssh libtheora libvdpau libvorbis libvpx libwebp libX11
      libxcb libXv libXext lzma openal openjpeg libpulseaudio rtmpdump opencore-amr
      samba SDL2 soxr speex srt vid-stab vo-amrwbenc wavpack x264 x265 xavs xvidcore
      zeromq4 zlib
    ] ++ optionals openglExtlib [ libGL libGLU ]
      ++ optionals nonfreeLicensing [ fdk_aac openssl ]
  