Prepare for using GYP build on buildbots

SConstruct

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 1583 matching lines @@
 # env.Copy without getting warnings for compatibility with older
 # version of scons.  Also, there's a bug in some revisions that
 # doesn't allow this flag to be set, so we swallow any exceptions.
 # Lovely.
 try:
   SetOption('warn', 'no-deprecated')
 except:
   pass
 
 
+def WarnAboutDeprecation():
+  print """
+#######################################################
+#  WARNING: Building V8 with SCons is deprecated and  #
+#  will not work much longer. Please switch to using  #
+#  the GYP-based build now. Instructions are at       #
+#  http://code.google.com/p/v8/wiki/BuildingWithGYP.  #
+#######################################################
+  """
+
+WarnAboutDeprecation()
+import atexit
+atexit.register(WarnAboutDeprecation)
 Build()