Add option 'env' to the SCons build scripts to support overriding the

ENV part of the build environment. This is mostly to support Windows
builds in cases where SCons cannot find the correct paths to the
Windows SDK, as these paths cannot be passed through shell envrionment
variables.


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@87 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

SConstruct

@@ -299,6 +299,7 @@ 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)', '')
   for (name, option) in SIMPLE_OPTIONS.items():
     help = '%s (%s)' % (name, ", ".join(option['values']))
     result.Add(name, help, option.get('default'))
@@ -336,11 +337,12 @@ def VerifyOptions(env):
 
 class BuildContext(object):
 
-  def __init__(self, options, samples):
+  def __init__(self, options, env_overrides, samples):
     self.library_targets = []
     self.cctest_targets = []
     self.sample_targets = []
     self.options = options
+    self.env_overrides = env_overrides
     self.samples = samples
     self.use_snapshot = (options['snapshot'] == 'on')
     self.flags = None
@@ -387,13 +389,24 @@ def PostprocessOptions(options):
     options['arch'] = options['simulator']
 
 
-def BuildSpecific(env, mode):
+def ParseEnvOverrides(arg):
+  # The environment overrides are in the format NAME1:value1,NAME2:value2
+  overrides = {}
+  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}
   for option in SIMPLE_OPTIONS:
     options[option] = env[option]
   PostprocessOptions(options)
 
-  context = BuildContext(options, samples=SplitList(env['sample']))
+  context = BuildContext(options, env_overrides, samples=SplitList(env['sample']))
 
   library_flags = context.AddRelevantFlags(os.environ, LIBRARY_FLAGS)
   v8_flags = context.AddRelevantFlags(library_flags, V8_EXTRA_FLAGS)
@@ -464,13 +477,14 @@ def Build():
   env = Environment(options=opts)
   Help(opts.GenerateHelpText(env))
   VerifyOptions(env)
+  env_overrides = ParseEnvOverrides(env['env'])
   
   libraries = []
   cctests = []
   samples = []
   modes = SplitList(env['mode'])
   for mode in modes:
-    context = BuildSpecific(env.Copy(), mode)
+    context = BuildSpecific(env.Copy(), mode, env_overrides)
     libraries += context.library_targets
     cctests += context.cctest_targets
     samples += context.sample_targets

src/SConscript

@@ -97,6 +97,7 @@ def Abort(message):
 def ConfigureObjectFiles():
   env = Environment()
   env.Replace(**context.flags['v8'])
+  env['ENV'].update(**context.env_overrides)
   env['BUILDERS']['JS2C'] = Builder(action=js2c.JS2C)
   env['BUILDERS']['Snapshot'] = Builder(action='$SOURCE $TARGET --logfile $LOGFILE')