Suppress warnings in the new SCons version about an obscure...

build/SConscript.main

 # Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import os
 import shutil
 import sys
 
 
 p = ARGUMENTS.get('PROGRESS')
 if p == 'spinner':
   Progress(['/\r', '|\r', '\\\r', '-\r'], interval=5, file=open('con', 'w'))
 elif p == 'name':
   Progress('$TARGET\r', overwrite=True, file=open('con', 'w'))
 
 
-SetOption('warn', ['no-missing-sconscript'] + GetOption('warn'))
+default_warnings = ['no-missing-sconscript', 'no-no-parallel-support']
+SetOption('warn', default_warnings + GetOption('warn'))
 
 
 load = ARGUMENTS.get('LOAD')
 if load:
     load = load.split(',')
 else:
     load = []
 
 
 env = Environment(
@@ skipping 510 matching lines @@
     initial_indent = ' '*32,
     subsequent_indent = ' '*32,
   )
   components = tw.fill(', '.join(components))
 
   Help(help_fmt % components)
 
 
 Import('build_component')
 Default(build_component)