anchor.diff:        (ifMinVer "0.6" "--disable-doc")
       # External Libraries
         "--enable-bzlib"
  +      "--enable-gnutls"
         (ifMinVer "1.0" "--enable-fontconfig")
         (ifMinVer "0.7" "--enable-libfreetype")
         "--enable-libmp3lame"
  
positive.code: { stdenv, fetchurl, pkgconfig, perl, texinfo, yasm
  , alsaLib, bzip2, fontconfig, freetype, libiconv, lame, libass, libogg, libtheora
  , libva, libvdpau, libvorbis, libvpx, lzma, pulseaudio, SDL, soxr, x264
  , xvidcore, zlib
  , openglSupport ? false, mesa ? null
  # Build options
  , runtimeCpuDetectBuild ? true # Detect CPU capabilities at runtime
  
negative.code:   nativeBuildInputs = [ perl pkgconfig texinfo yasm ];
  
    buildInputs = [
      bzip2 fontconfig freetype gnutls libiconv lame libass libogg libtheora
      libvdpau libvorbis lzma SDL soxr x264 xvidcore zlib
    ] ++ optional openglSupport mesa
      ++ optionals (!isDarwin) [ libvpx pulseaudio ] # Need to be fixed on Darwin
      ++ optional (isLinux || isFreeBSD) libva
  