anchor.diff:      "treat_warnings_as_errors=false"
       "v8_enable_i18n_support=true"
       "use_gold=false"
  -    "use_system_xcode=true"
  +    "init_stack_vars=false"
       # ''custom_toolchain="//build/toolchain/linux/unbundle:default"''
       ''host_toolchain="//build/toolchain/linux/unbundle:default"''
       ''v8_snapshot_toolchain="//build/toolchain/linux/unbundle:default"''
     ] ++ lib.optional stdenv.cc.isClang ''clang_base_path="${stdenv.cc}"'';
   
     NIX_CFLAGS_COMPILE = "-O2";
  +  FORCE_MAC_SDK_MIN = stdenv.targetPlatform.sdkVer or "10.12";
   
  -  nativeBuildInputs = [ gn ninja pkg-config python ]
  -    ++ lib.optionals stdenv.isDarwin [ xcbuild darwin.DarwinTools ];
  +  nativeBuildInputs = [
  +    gn
  +    ninja
  +    pkg-config
  +    python
  +  ] ++ lib.optionals stdenv.isDarwin [
  +    xcbuild
  +    darwin.DarwinTools
  +    pythonPackages.setuptools
  +  ];
     buildInputs = [ glib icu ];
   
     ninjaFlags = [ ":d8" "v8_monolith" ];
  
positive.code: { stdenv, lib, fetchgit, fetchFromGitHub
  , gn, ninja, python, glib, pkg-config, icu
  , xcbuild, darwin
  , fetchpatch
  }:
  
negative.code:     "is_clang=${lib.boolToString stdenv.cc.isClang}"
      "use_sysroot=false"
      # "use_system_icu=true"
      "clang_use_chrome_plugins=false"
      "is_component_build=false"
      "v8_use_external_startup_data=false"
      "v8_monolithic=true"
  