- Added option to set SourceSignatures in scons.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@210 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

SConstruct

@@ -294,6 +294,11 @@ SIMPLE_OPTIONS = {
     'values': ['on', 'off'],
     'default': 'off',
     'help': 'enable the disassembler to inspect generated code'
+  },
+  'sourcesignatures': {
+    'values': ['MD5', 'timestamp'],
+    'default': 'MD5',
+    'help': 'set how the build system detects file changes'
   }
 }
 
@@ -492,6 +497,8 @@ def Build():
   VerifyOptions(env)
   env_overrides = ParseEnvOverrides(env['env'])
   
+  SourceSignatures(env['sourcesignatures'])
+  
   libraries = []
   cctests = []
   samples = []