Fix python scripts in src/build/

build/compiler_version.py

-#!/usr/bin/python
-
+#!/usr/bin/env python
 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Compiler version checking tool for gcc
 
 Print gcc version as XY if you are running gcc X.Y.*.
 This is used to tweak build flags for gcc 4.4.
 """
 
@@ skipping 28 matching lines @@
     # Otherwise we check the g++ version.
     gccversion = GetVersion("g++")
     if gccversion != "":
       print gccversion
       return 0
 
   return 1
 
 if __name__ == "__main__":
   sys.exit(main())