Workaround for T441, enumerate optimization bug.

Cython/Compiler/Optimize.py

@@ -237,6 +237,10 @@ class IterationTransform(Visitor.VisitorTransform):
             # nothing we can do here, I guess
             return node
         
+        if iterable_target.type is not PyrexTypes.py_object_type:
+            # this may need conversion, could be made to work
+            return node
+
         temp = UtilNodes.LetRefNode(ExprNodes.IntNode(enumerate_function.pos,
                                                       value='0',
                                                       type=counter_type,