anchor.diff:        printer.writeProgramFile(program);
         await sink.close();
         _outputStream.writeln('$boundaryKey $_kernelBinaryFilename');
  +
  +      final String depfile = options['depfile'];
  +      if (depfile != null) {
  +        await _writeDepfile(program, _kernelBinaryFilename, depfile);
  +      }
  +
         _kernelBinaryFilename = _kernelBinaryFilenameIncremental;
       } else
         _outputStream.writeln(boundaryKey);
  
positive.code:             print: (Zone self, ZoneDelegate parent, Zone zone, String line) =>
                  _outputStream.writeln(line)));
    }
  }
  
  /// Entry point for this module, that creates `_FrontendCompiler` instance and
  
negative.code:   ..addOption('output-incremental-dill',
        help: 'Output path for the generated incremental dill',
        defaultsTo: null)
    ..addOption('depfile',
        help: 'Path to output Ninja depfile. Only used in batch mode.')
    ..addOption('packages',
        help: '.packages file to use for compilation',
        defaultsTo: null)
  