anchor.diff:          "8"
       }"
       "--chroma-format=all"
  -    "--enable-asm"
  -    "--disable-debug"
  -    "--disable-gprof"
       "--enable-pic"
       "--disable-avs"
       "--disable-swscale"
  
positive.code: }:
  
  let
    version = "20160916";
  in
  stdenv.mkDerivation rec {
    name = "x264-${version}";
  
negative.code:   '';
  
    configureFlags = [
      "--enable-shared"
      "--disable-win32thread"
      "--disable-interlaced"
      "--bit-depth=${
  