Fixed SCons build when not running from the V8 root directory

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 595 matching lines @@
   MAJOR_VERSION_PATTERN = re.compile(r"#define\s+MAJOR_VERSION\s+(.*)")
   MINOR_VERSION_PATTERN = re.compile(r"#define\s+MINOR_VERSION\s+(.*)")
   BUILD_NUMBER_PATTERN = re.compile(r"#define\s+BUILD_NUMBER\s+(.*)")
   PATCH_LEVEL_PATTERN = re.compile(r"#define\s+PATCH_LEVEL\s+(.*)")
 
   patterns = [MAJOR_VERSION_PATTERN,
               MINOR_VERSION_PATTERN,
               BUILD_NUMBER_PATTERN,
               PATCH_LEVEL_PATTERN]
 
-  source = open(join('src', 'version.cc')).read()
+  source = open(join(root_dir, 'src', 'version.cc')).read()
   version_components = []
   for pattern in patterns:
     match = pattern.search(source)
     if match:
       version_components.append(match.group(1).strip())
     else:
       version_components.append('0')
 
   return version_components
 
 
 def GetVersion():
   version_components = GetVersionComponents()
   
   if version_components[len(version_components) - 1] == '0':
     version_components.pop()
   return '.'.join(version_components)
 
 
 def GetSpecificSONAME():
   SONAME_PATTERN = re.compile(r"#define\s+SONAME\s+\"(.*)\"")
   
-  source = open(join('src', 'version.cc')).read()
+  source = open(join(root_dir, 'src', 'version.cc')).read()
   match = SONAME_PATTERN.search(source)
   
   if match:
     return match.group(1).strip()
   else:
     return ''
 
 
 def SplitList(str):
   return [ s for s in str.split(",") if len(s) > 0 ]
@@ skipping 264 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()