anchor.diff:              useiOSCross = true;
               libc = "libSystem";
             };
  -
  -          config.allowUnfree = true;
  -          config.packageOverrides = p: {
  -            darwin = p.darwin // {
  -              ios-cross = p.darwin.ios-cross.override {
  -                # Depending on where ghcHEAD is in your nixpkgs checkout, you may need llvm 39 here instead
  -                inherit (p.llvmPackages_39) llvm clang;
  -              };
  -            };
  -            osx_sdk = p.callPackage ({ stdenv }:
  -              let version = "10";
  -              in stdenv.mkDerivation rec {
  -              name = "iOS.sdk";
  -
  -              src = stdenv.ccCross.sdk;
  -
  -              unpackPhase    = "true";
  -              configurePhase = "true";
  -              buildPhase     = "true";
  -              setupHook = ./setup-hook-ios.sh;
  -
  -              installPhase = ''
  -                mkdir -p $out/
  -                echo "Source is: $src"
  -                cp -r $src/* $out/
  -              '';
  -
  -              meta = with stdenv.lib; {
  -                description = "The IOS OS ${version} SDK";
  -                maintainers = with maintainers; [ copumpkin ];
  -                platforms   = platforms.darwin;
  -                license     = licenses.unfree;
  -              };
  -            }) {};
  +          inherit config;
  +        };
  +        arm64 = nixpkgsFunc {
  +          crossSystem = 
  +            let cfg = {
  +              # You can change config/arch/isiPhoneSimulator depending on your target:
  +              # aarch64-apple-darwin14 | arm64  | false
  +              # arm-apple-darwin10     | armv7  | false
  +              # i386-apple-darwin11    | i386   | true
  +              # x86_64-apple-darwin14  | x86_64 | true
  +              config = "aarch64-apple-darwin14";
  +              arch = "arm64";
  +              isiPhoneSimulator = false;
  +            }; in {
  +            inherit (cfg) config arch isiPhoneSimulator;
  +            useiOSCross = true;
  +            libc = "libSystem";
             };
  +          inherit config;
           };
         };
       };
  
positive.code:       if system == null then {} else { inherit system; }
      ));
      nixpkgsCross = {
        ios = {
          simulator64 = nixpkgsFunc {
            crossSystem = 
              let cfg = {
  
negative.code: 
      } // (if useTextJSString then overridesForTextJSString self super else {});
    };
    inherit nixpkgs overrideCabal extendHaskellPackages ghc ghc7 ghc7_8 ghcIosSimulator64 ghcIosArm64;
    stage2Script = nixpkgs.runCommand "stage2.nix" {
      GEN_STAGE2 = builtins.readFile (nixpkgs.path + "/pkgs/development/compilers/ghcjs/gen-stage2.rb");
      buildCommand = ''
  