anchor.diff:    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 libssh libtheora libvdpau libvorbis libvpx libwebp libX11
  +    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
  
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: #, 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
  