anchor.diff:  
     buildInputs = [
       bzip2 fontconfig freetype gnutls libiconv lame libass libogg libtheora
  -    libvdpau libvorbis lzma SDL soxr x264 xvidcore zlib libopus
  +    libvdpau libvorbis lzma SDL soxr x264 x265 xvidcore zlib libopus
     ] ++ optional openglSupport mesa
       ++ optionals (!isDarwin && !isArm) [ libvpx libpulseaudio ] # Need to be fixed on Darwin and ARM
       ++ optional ((isLinux || isFreeBSD) && !isArm) libva
  
positive.code: { stdenv, fetchurl, pkgconfig, perl, texinfo, yasm
  , alsaLib, bzip2, fontconfig, freetype, gnutls, libiconv, lame, libass, libogg
  , libtheora, libva, libvorbis, libvpx, lzma, libpulseaudio, soxr
  , x264, xvidcore, zlib, libopus
  , openglSupport ? false, mesa ? null
  # Build options
  , runtimeCpuDetectBuild ? true # Detect CPU capabilities at runtime
  
negative.code:       "--enable-libxvid"
        "--enable-zlib"
        (ifMinVer "2.8" "--enable-libopus")
        (ifMinVer "2.8" "--enable-libx265")
      # Developer flags
        (enableFeature debugDeveloper "debug")
        (enableFeature optimizationsDeveloper "optimizations")
  