Convert from using env['PLATFORM'] directly to using the more flexible...

net/net.scons

 # 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.
 
 __doc__ = """
 Master configuration for building net components.
 """
 
 Import('env')
 
 # Arrange for Hammer to add all programs to the 'net' Alias.
 env.Append(
     COMPONENT_PROGRAM_GROUPS = ['net'],
     COMPONENT_TEST_PROGRAM_GROUPS = ['net'],
 )
 
 sconscript_files = [
     'crash_cache.scons',
     'dump_cache.scons',
     'net_lib.scons',
     'net_perftests.scons',
     'net_unittests.scons',
     'stress_cache.scons',
 ]
 
-if env['PLATFORM'] in ('posix', 'darwin'):
+if env.Bit('posix'):
   # Remove *.scons files whose targets still need to be ported.
   # TODO(port): delete files from this list as they get ported.
   to_be_ported = [
         'crash_cache.scons',
   ]
   for remove in to_be_ported:
     sconscript_files.remove(remove)
 
-if env['PLATFORM'] == 'win32':
+if env.Bit('windows'):
   # TODO: We need to port tld_cleanup before this will work on other
   # platforms.
   sconscript_files.extend([
       'net_resources.scons',
       'tools/tld_cleanup/tld_cleanup.scons',
   ])
 
 SConscript(sconscript_files, exports=['env'])