anchor.diff:  { stdenv, fetchurl, pkgconfig, perl, texinfo, yasm
   , alsaLib, bzip2, fontconfig, freetype, gnutls, libiconv, lame, libass, libogg
   , libssh, libtheora, libva, libdrm, libvorbis, libvpx, lzma, libpulseaudio, soxr
  -, x264, x265, xvidcore, zlib, libopus, speex, nv-codec-headers
  +, x264, x265, xvidcore, zlib, libopus, speex, nv-codec-headers, dav1d
   , openglSupport ? false, libGLU_combined ? null
   # Build options
   , runtimeCpuDetectBuild ? true # Detect CPU capabilities at runtime
  
positive.code:     ++ optional isLinux alsaLib
      ++ optionals isDarwin darwinFrameworks
      ++ optional vdpauSupport libvdpau
      ++ optional sdlSupport (if reqMin "3.2" then SDL2 else SDL);
  
    enableParallelBuilding = true;
  
  
negative.code:       (ifMinVer "2.8" "--enable-libopus")
        "--enable-libspeex"
        (ifMinVer "2.8" "--enable-libx265")
        (ifMinVer "4.2" (enableFeature (dav1d != null) "libdav1d"))
      # Developer flags
        (enableFeature debugDeveloper "debug")
        (enableFeature optimizationsDeveloper "optimizations")
  