anchor.diff:  Future<void> _run(
     String exe,
     List<String> args, {
  +  Uri? output,
     Map<String, String>? environment,
   }) async {
     print('\n$exe ${args.join(' ')}\n');
  
positive.code:       srcDir.resolve('Cargo.toml').toFilePath(),
        '--release'
      ],
      environment: {
        if (args['clang'] != null) 'CC': clang,
        if (args['clangpp'] != null) ...{
  
negative.code:   if (result != 0) {
      throw ProcessException(exe, args, '', result);
    }
    if (output != null && !File.fromUri(output).existsSync()) {
      throw FileSystemException(
        'Command succeded, but the output file is missing',
        output.toFilePath(),
      );
    }
  }
  
  String _toUpperUnderscore(String string) {
  