Index: Lib/inspect.py
===================================================================
--- Lib/inspect.py	(revision 74214)
+++ Lib/inspect.py	(working copy)
@@ -947,7 +947,10 @@
         tb = tb.tb_next
     return framelist
 
-currentframe = sys._getframe
+if hasattr(sys, '_getframe'):
+    currentframe = sys._getframe
+else:
+    currentframe = lambda: None
 
 def stack(context=1):
     """Return a list of records for the stack above the caller's frame."""