Fix the archive code so that it compiles in a stricter mode.

utils/archive/options.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #library('options');
 
 /**
  * An individual option.
  */
 class ArchiveOption {
@@ skipping 29 matching lines @@
    */
   void operator[]=(String name, value) {
     _options[name] = new ArchiveOption(name, value);
   }
 
   /** Gets the option with the given name. */
   ArchiveOption operator[](String name) {
     return _options[name];
   }
 
-  /**
-   * Serializes the options to the format understood by libarchive.
-   *
-   * Meant for internal use.
-   */
-  String serialize() {
-    return Strings.join(_options.getValues().map((option) {
-      if (option.value is Boolean) {
-        return '${option.value ? '!' : ''}${option.name}';
-      } else {
-        return '${option.name}=${option.value}';
-      }
-    }), ',');
-  }
+  /** Gets all options. */
+  List<ArchiveOption> get all() => _options.getValues();
 }