Apply Lei Zhang's patch to add easy import of additional environment...

SConstruct

 # Copyright 2008 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 490 matching lines @@
     'help': 'the console to use for the d8 shell'
   }
 }
 
 
 def GetOptions():
   result = Options()
   result.Add('mode', 'compilation mode (debug, release)', 'release')
   result.Add('sample', 'build sample (shell, process)', '')
   result.Add('env', 'override environment settings (NAME1:value1,NAME2:value2)', '')
+  result.Add('importenv', 'import environment settings (NAME1,NAME2)', '')

[Kevin Millikin (Chromium), 2009/04/02 12:54:11]

Might be clearer to have the message string:

'import environment settings (NAME1,NAME2,...)'

Also, consider zero-based indexing.  :)

   for (name, option) in SIMPLE_OPTIONS.iteritems():
     help = '%s (%s)' % (name, ", ".join(option['values']))
     result.Add(name, help, option.get('default'))
   return result
 
 
 def SplitList(str):
   return [ s for s in str.split(",") if len(s) > 0 ]
 
 
@@ skipping 98 matching lines @@
 
 def PostprocessOptions(options):
   # Adjust architecture if the simulator option has been set
   if (options['simulator'] != 'none') and (options['arch'] != options['simulator']):
     if 'arch' in ARGUMENTS:
       # Print a warning if arch has explicitly been set
       print "Warning: forcing architecture to match simulator (%s)" % options['simulator']
     options['arch'] = options['simulator']
 
 
-def ParseEnvOverrides(arg):
+def ParseEnvOverrides(arg, imports):
   # The environment overrides are in the format NAME1:value1,NAME2:value2
+  # The environment imports are in the format NAME1,NAME2

[Kevin Millikin (Chromium), 2009/04/02 12:54:11]

Analogously here.

   overrides = {}
+  for var in imports.split(','):
+    if var in os.environ:
+      overrides[var] = os.environ[var]
   for override in arg.split(','):
     pos = override.find(':')
     if pos == -1:
       continue
     overrides[override[:pos].strip()] = override[pos+1:].strip()
   return overrides
 
 
 def BuildSpecific(env, mode, env_overrides):
   options = {'mode': mode}
@@ skipping 77 matching lines @@
   context.cctest_targets.append(cctest_program)
 
   return context
 
 
 def Build():
   opts = GetOptions()
   env = Environment(options=opts)
   Help(opts.GenerateHelpText(env))
   VerifyOptions(env)
-  env_overrides = ParseEnvOverrides(env['env'])
+  env_overrides = ParseEnvOverrides(env['env'], env['importenv'])
 
   SourceSignatures(env['sourcesignatures'])
 
   libraries = []
   mksnapshots = []
   cctests = []
   samples = []
   d8s = []
   modes = SplitList(env['mode'])
   for mode in modes:
@@ skipping 21 matching lines @@
 # 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
 
 
 Build()