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