**/*.py: use /usr/bin/env to find python

toolchain_build/once.py

-#!/usr/bin/python
+#!/usr/bin/env python
 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Memoize the data produced by slow operations into Google storage.
 
 Caches computations described in terms of command lines and inputs directories
 or files, which yield a set of output file.
 """
 
@@ skipping 238 matching lines @@
     h = hashlib.sha1()
     h.update('package:' + package)
     h.update('summary:' + self.SystemSummary())
     for command in commands:
       h.update('command:')
       h.update(str(command))
     for key in sorted(inputs.keys()):
       h.update('item_name:' + key + '\x00')
       h.update('item:' + hashing_tools.StableHashPath(inputs[key]))
     return h.hexdigest()