PEP 3123: Provide forward compatibility with Python 3.0, while keeping
backwards compatibility. Add Py_Refcnt, Py_Type, Py_Size, and
PyVarObject_HEAD_INIT.
diff --git a/Include/descrobject.h b/Include/descrobject.h
index a74af60..a45a801 100644
--- a/Include/descrobject.h
+++ b/Include/descrobject.h
@@ -77,7 +77,7 @@
 					       struct PyGetSetDef *);
 PyAPI_FUNC(PyObject *) PyDescr_NewWrapper(PyTypeObject *,
 						struct wrapperbase *, void *);
-#define PyDescr_IsData(d) ((d)->ob_type->tp_descr_set != NULL)
+#define PyDescr_IsData(d) (Py_Type(d)->tp_descr_set != NULL)
 
 PyAPI_FUNC(PyObject *) PyDictProxy_New(PyObject *);
 PyAPI_FUNC(PyObject *) PyWrapper_New(PyObject *, PyObject *);