anchor.diff: -{ stdenv, fetchurl, fetchpatch, cmake, nasm, numactl
  +{ stdenv, fetchFromBitbucket, cmake, nasm, numactl
   , numaSupport ? stdenv.hostPlatform.isLinux && (stdenv.hostPlatform.isx86 || stdenv.hostPlatform.isAarch64)  # Enabled by default on NUMA platforms
   , debugSupport ? false # Run-time sanity checks (debugging)
   , werrorSupport ? false # Warnings as errors
  
positive.code: 
  stdenv.mkDerivation rec {
    pname = "x265";
    inherit version src patches;
  
    enableParallelBuilding = true;
  
    postPatch = ''
      sed -i 's/unknown/${version}/g' source/cmake/version.cmake
    '';
  
    cmakeFlags = [
  
negative.code:     (mkFlag werrorSupport "WARNINGS_AS_ERRORS")
    ];
  
    version = "3.4";
  
    src = fetchFromBitbucket {
      owner = "multicoreware";
      repo = "x265_git";
      rev = "${version}";
      sha256 = "1jzgv2hxhcwmsdf6sbgyzm88a46dp09ll1fqj92g9vckvh9a7dsn";
    };
  
    buildLib = has12Bit: stdenv.mkDerivation rec {
      name = "libx265-${if has12Bit then "12" else "10"}-${version}";
      inherit src;
      enableParallelBuilding = true;
  
      postPatch = ''
        sed -i 's/unknown/${version}/g' source/cmake/version.cmake
        sed -i 's/0.0/${version}/g' source/cmake/version.cmake
      '';
  
      cmakeLibFlags = [
  