anchor.diff:      ++ optionals x11grabExtlib [ xorg.libXext xorg.libXfixes ]
       ++ optionals nonfreeLicensing [ faac fdk_aac openssl ];
   
  +  NIX_CFLAGS_COMPILE = optionals nvenc [
  +    "-I${nvidia-video-codec-sdk}/include"
  +  ];
  +
     # Build qt-faststart executable
     postBuild = optional qtFaststartProgram ''make tools/qt-faststart'';
     postInstall = optional qtFaststartProgram ''cp -a tools/qt-faststart $out/bin/'';
  
positive.code:  *
   * Not packaged:
   *   aacplus avisynth cdio-paranoia crystalhd libavc1394 libiec61883
   *   libmxf libnut libquvi nvenc opencl opencore-amr openh264 oss shine twolame
   *   utvideo vo-aacenc vo-amrwbenc xvmc zvbi blackmagic-design-desktop-video
   *
   * Not supported:
  
negative.code: , libxcbxfixesExtlib ? true # X11 grabbing mouse rendering
  , libxcbshapeExtlib ? true # X11 grabbing shape rendering
  , lzma ? null # xz-utils
  , nvenc ? false # NVIDIA NVENC support
    , nvidia-video-codec-sdk ? null
  , openal ? null # OpenAL 1.1 capture support
  #, opencl ? null # OpenCL code
  #, opencore-amr ? null # AMR-NB de/encoder & AMR-WB decoder
  