anchor.diff:  
   import 'dart:io';
   import 'dart:async';
  +import 'package:args/args.dart' show ArgParser;
   import 'package:dev_compiler/src/compiler/module_builder.dart';
   import 'package:dev_compiler/src/kernel/target.dart';
   import 'package:dev_compiler/src/kernel/command.dart';
  
positive.code:   // writeProgramToText(program);
    await writeProgramToBinary(program, outputPath);
  
    bool generateJS = false;
    if (generateJS) {
      var jsModule = compileToJSModule(program, [], [], {});
      var jsPath = path.join(path.basename(outputPath), 'dart_sdk.kernel.js');
  
negative.code: import 'patch_sdk.dart' as patch_sdk;
  
  Future main(List<String> args) async {
    // Parse flags.
    var parser = new ArgParser()
      ..addFlag('generate-javascript',
          help: 'Generate JavaScript (in addition to dill)', abbr: 'g');
    var parserOptions = parser.parse(args);
    var generateJS = parserOptions['generate-javascript'] as bool;
    var rest = parserOptions.rest;
  
    Directory.current = path.dirname(path.dirname(path.fromUri(Platform.script)));
  
    var outputPath =
        path.absolute(rest.length > 0 ? rest[0] : 'gen/sdk/ddc_sdk.dill');
  
    patch_sdk.main(['../..', 'tool/input_sdk', 'gen/patched_sdk']);
  
  