Prepend the tools directory to python module path

SConstruct

 # Copyright 2010 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 14 matching lines @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 import platform
 import re
 import sys
 import os
 from os.path import join, dirname, abspath
 from types import DictType, StringTypes
 root_dir = dirname(File('SConstruct').rfile().abspath)
-sys.path.append(join(root_dir, 'tools'))
+sys.path.insert(0, join(root_dir, 'tools'))
 import js2c, utils
 
 # ANDROID_TOP is the top of the Android checkout, fetched from the environment
 # variable 'TOP'.   You will also need to set the CXX, CC, AR and RANLIB
 # environment variables to the cross-compiling tools.
 ANDROID_TOP = os.environ.get('TOP')
 if ANDROID_TOP is None:
   ANDROID_TOP=""
 
 # ARM_TARGET_LIB is the path to the dynamic library to use on the target
@@ skipping 1144 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()