anchor.diff:   */
   
   let
  -  inherit (stdenv) isCygwin isDarwin isFreeBSD isLinux;
  +  inherit (stdenv) isCygwin isDarwin isFreeBSD isLinux isAarch64;
     inherit (stdenv.lib) optional optionals optionalString enableFeature;
   in
   
  
positive.code: , libXv ? null # Xlib support
  , libXext ? null # Xlib support
  , lzma ? null # xz-utils
  , nvenc ? !stdenv.isDarwin, nv-codec-headers ? null # NVIDIA NVENC support
  , openal ? null # OpenAL 1.1 capture support
  #, opencl ? null # OpenCL code
  , opencore-amr ? null # AMR-NB de/encoder & AMR-WB decoder
  
negative.code:  *   libvpx(stable 1.3.0) openal openjpeg pulseaudio rtmpdump samba vid-stab
   *   wavpack x265 xavs
   *
   * Need fixes to support AArch64:
   *   libmfx(intel-media-sdk) nvenc
   *
   * Not supported:
   *   stagefright-h264(android only)
   *
  