anchor.diff:      libogg libopus librsvg libssh libtheora libvdpau libvorbis libvpx libwebp libX11
       libxcb libXv libXext xz openal openjpeg libpulseaudio rav1e svt-av1 rtmpdump opencore-amr
       samba SDL2 soxr speex srt vid-stab vo-amrwbenc x264 x265 xavs xvidcore
  -    zeromq4 zlib
  +    zeromq4 zlib glslang
     ] ++ optionals openglExtlib [ libGL libGLU ]
       ++ optionals nonfreeLicensing [ fdk_aac openssl ]
       ++ optional ((isLinux || isFreeBSD) && libva != null) libva
       ++ optional (!isAarch64 && libvmaf != null && version3Licensing) libvmaf
  -    ++ optionals isLinux [ alsaLib libraw1394 libv4l ]
  +    ++ optionals isLinux [ alsaLib libraw1394 libv4l vulkan-loader ]
       ++ optional (isLinux && !isAarch64 && libmfx != null) libmfx
       ++ optional nvenc nv-codec-headers
       ++ optionals stdenv.isDarwin [ Cocoa CoreServices CoreAudio AVFoundation
  
positive.code: , xvidcore ? null # Xvid encoder, native encoder exists
  , zeromq4 ? null # Message passing
  , zlib ? null
  #, zvbi ? null # Teletext support
  /*
   *  Developer options
  
negative.code:     (enableFeature (xvidcore != null && gplLicensing) "libxvid")
      (enableFeature (zeromq4 != null) "libzmq")
      (enableFeature (zlib != null) "zlib")
      (enableFeature (isLinux && vulkan-loader != null) "vulkan")
      (enableFeature (glslang != null) "libglslang")
      #(enableFeature (zvbi != null && gplLicensing) "libzvbi")
      /*
       * Developer flags
  