anchor.diff:  #, libnut ? null # NUT (de)muxer, native (de)muser exists
   , libogg ? null # Ogg container used by vorbis & theora
   , libopus ? null # Opus de/encoder
  +, librsvg ? null # SVG protocol
   , libssh ? null # SFTP protocol
   , libtheora ? null # Theora encoder
   , libv4l ? null # Video 4 Linux support
  
positive.code:     (enableFeature (libmysofa != null) "libmysofa")
      #(enableFeature (libnut != null) "libnut")
      (enableFeature (libopus != null) "libopus")
      (enableFeature (libssh != null) "libssh")
      (enableFeature (libtheora != null) "libtheora")
      (enableFeature (if isLinux then libv4l != null else false) "libv4l2")
  
negative.code:   buildInputs = [
      bzip2 celt dav1d fontconfig freetype frei0r fribidi game-music-emu gnutls gsm
      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 vid-stab vo-amrwbenc wavpack x264 x265 xavs xvidcore
      zeromq4 zlib
  