Add a --[no]-packages-dir flag.

lib/src/command.dart

 // Copyright (c) 2013, 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.
 
 import 'package:args/args.dart';
 import 'package:args/command_runner.dart';
 
 import 'entrypoint.dart';
 import 'log.dart' as log;
 import 'global_packages.dart';
@@ skipping 19 matching lines @@
   }
   GlobalPackages _globals;
 
   /// Gets the [Entrypoint] package for the current working directory.
   ///
   /// This will load the pubspec and fail with an error if the current directory
   /// is not a package.
   Entrypoint get entrypoint {
     // Lazy load it.
     if (_entrypoint == null) {
-      _entrypoint = new Entrypoint('.', cache,
-          packageSymlinks: globalResults['package-symlinks']);
+      _entrypoint = new Entrypoint('.', cache);
     }
     return _entrypoint;
   }
   Entrypoint _entrypoint;
 
   /// The URL for web documentation for this command.
   String get docUrl => null;
 
   /// Override this and return `false` to disallow trailing options from being
   /// parsed after a non-option argument is parsed.
@@ skipping 29 matching lines @@
   /// If the parsing fails, prints a usage message and exits.
   int parseInt(String intString, String name) {
     try {
       return int.parse(intString);
     } on FormatException catch (_) {
       usageException('Could not parse $name "$intString".');
       return null;
     }
   }
 }