Change back to building everything if no argument to build.py was given

tools/build.py

 #!/usr/bin/env python
 #
 # 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.
 #
 
 import optparse
 import os
 import shutil
@@ skipping 291 matching lines @@
 def Main():
   utils.ConfigureJava()
   # Parse the options.
   parser = BuildOptions()
   (options, args) = parser.parse_args()
   if not ProcessOptions(options, args):
     parser.print_help()
     return 1
   # Determine which targets to build. By default we build the "all" target.
   if len(args) == 0:
-    # Note: The 'default' target doesn't depend on all targets. Developers have
-    # requested to exclude certain targets to keep build times down.
-    target = 'default'
+    if HOST_OS == 'macos':
+      target = 'All'
+    else:
+      target = 'all'
   else:
     target = args[0]
 
   filter_xcodebuild_output = False
   # Remember path
   old_path = os.environ['PATH']
   # Build the targets for each requested configuration.
   for target_os in options.os:
     for mode in options.mode:
       for arch in options.arch:
@@ skipping 80 matching lines @@
         process.wait()
         if process.returncode != 0:
           print "BUILD FAILED"
           return 1
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(Main())