anchor.diff:        (ifMinVer "1.2" "--enable-libsoxr")
         "--enable-libx264"
         "--enable-libxvid"
  +      "--enable-libzimg"
         "--enable-zlib"
         (ifMinVer "2.8" "--enable-libopus")
         "--enable-libspeex"
  
positive.code: { lib, stdenv, buildPackages, fetchurl, pkg-config, addOpenGLRunpath, perl, texinfo, yasm
  , alsa-lib, bzip2, fontconfig, freetype, gnutls, libiconv, lame, libass, libogg
  , libssh, libtheora, libva, libdrm, libvorbis, libvpx, xz, libpulseaudio, soxr
  , x264, x265, xvidcore, zlib, libopus, speex, nv-codec-headers, dav1d
  , srt ? null
  , openglSupport ? false, libGLU ? null, libGL ? null
  , libmfxSupport ? false, intel-media-sdk ? null
  
negative.code: 
    buildInputs = [
      bzip2 fontconfig freetype gnutls libiconv lame libass libogg libssh libtheora
      libvorbis xz soxr x264 x265 xvidcore zimg zlib libopus speex srt nv-codec-headers
    ] ++ optionals openglSupport [ libGL libGLU ]
      ++ optional libmfxSupport intel-media-sdk
      ++ optional libaomSupport libaom
  