anchor.diff:    ] ++ optionals (stdenv.hostPlatform != stdenv.buildPlatform) [
       "--cross-prefix=${stdenv.cc.targetPrefix}"
       "--enable-cross-compile"
  +  ] ++ optionals stdenv.cc.isClang [
  +    "--cc=clang"
  +    "--cxx=clang++"
     ];
   
     nativeBuildInputs = [ addOpenGLRunpath perl pkg-config texinfo yasm ];
  
positive.code:     (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
  
negative.code:     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
    ] ++ 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 vulkan-loader glslang ]
      ++ optional (isLinux && !isAarch64 && libmfx != null) libmfx
      ++ optional nvenc nv-codec-headers
      ++ optionals stdenv.isDarwin [ Cocoa CoreServices CoreAudio AVFoundation
  