diff -r f2c257820a73 Lib/importlib/__init__.py
--- a/Lib/importlib/__init__.py	Thu Mar 13 22:17:28 2014 -0400
+++ b/Lib/importlib/__init__.py	Fri Mar 14 09:35:02 2014 -0400
@@ -22,7 +22,12 @@
     # a second copy of the module.
     _bootstrap.__name__ = 'importlib._bootstrap'
     _bootstrap.__package__ = 'importlib'
-    _bootstrap.__file__ = __file__.replace('__init__.py', '_bootstrap.py')
+    try:
+        _bootstrap.__file__ = __file__.replace('__init__.py', '_bootstrap.py')
+    except NameError:
+        # __file__ is not guaranteed to be defined, e.g. if this code gets
+        # frozen by a tool like cx_Freeze.
+        pass
     sys.modules['importlib._bootstrap'] = _bootstrap
 
 # To simplify imports in test code