Issue #6477: Merge with 3.3.

diff --cc Include/object.h
Simple merge

diff --cc Modules/_pickle.c
Simple merge

diff --cc Objects/object.c
index 8ccc91cd4b9def460abcc14090bf05a735c8748e,e079d5104b54f874a25ef706c8a6dc5c4948cba8..62bdb49d13667b03175addb9ff6041b16c081300
--- 1/Objects/object.c
--- 2/Objects/object.c
+++ b/Objects/object.c
@@@ -1485,16 -1524,7 +1485,16 @@@ notimplemented_new(PyTypeObject *type, 
      Py_RETURN_NOTIMPLEMENTED;
  }
  
- PyTypeObject PyNotImplemented_Type = {
 +static void
 +notimplemented_dealloc(PyObject* ignore)
 +{
 +    /* This should never get called, but we also don't want to SEGV if
 +     * we accidentally decref NotImplemented out of existence.
 +     */
 +    Py_FatalError("deallocating NotImplemented");
 +}
 +
+ PyTypeObject _PyNotImplemented_Type = {
      PyVarObject_HEAD_INIT(&PyType_Type, 0)
      "NotImplementedType",
      0,