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

third_party/libxslt/libxslt.scons

 # Copyright 2008, Google Inc.
 # 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
@@ skipping 37 matching lines @@
 )
 
 env.Append(
     CPPDEFINES = [
         'U_STATIC_IMPLEMENTATION',
         'LIBXML_STATIC',
         'LIBXSLT_STATIC',
     ],
 )
 
-if env['PLATFORM'] == 'win32':
+if env.Bit('windows'):
   env.Append(
       CCFLAGS = [
           '/TC',
           '/wd4800',
       ],
   )
 
 
 input_files = [
     'libxslt/attributes.c',
@@ skipping 12 matching lines @@
     'libxslt/templates.c',
     'libxslt/transform.c',
     'libxslt/variables.c',
     'libxslt/xslt.c',
     'libxslt/xsltutils.c',
 ]
 
 env.ChromeStaticLibrary('libxslt', input_files)
 
 
-if env['PLATFORM'] == 'win32':
+if env.Bit('windows'):
   config_files = [
       # The configure.js script must be first in this list; the
       # env.Command() call below executes the first list element.
 
       'win32/configure.js',
       'win32/Makefile.msvc',
 
       'config.h.in',
       'configure.in',
       'libexslt.pc.in',
@@ skipping 11 matching lines @@
 
   copied_sources = []
   for cf in config_files:
     result = env.Command('scons/' + cf, cf, Copy('$TARGET', '$SOURCE'))
     copied_sources.extend(result)
 
   env.Command(['scons/config.h'],
               copied_sources,
               'cd ${SOURCE.dir} && $CSCRIPT ${SOURCE.file} $CONFIG_OPTIONS',
               CONFIG_OPTIONS='compiler=msvc')
-elif env['PLATFORM'] == 'posix':
+elif env.Bit('linux'):
   config_files = [
       'config.h',
       'xslt-config',
       'libexslt/exsltconfig.h',
       'libxslt/xsltconfig.h',
       'libxslt/xsltwin32config.h',
   ]
   for cf in config_files:
     result = env.Command('scons/' + cf, 'linux/' + cf,
                          Copy('$TARGET', '$SOURCE'))