Rename _PyIter_GetBuiltin to _PyObject_GetBuiltin, and do not include it in the stable ABI.
diff --git a/Objects/setobject.c b/Objects/setobject.c
index 7cd87d3..b903fbee 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -856,7 +856,7 @@
         Py_DECREF(list);
         return NULL;
     }
-    return Py_BuildValue("N(N)", _PyIter_GetBuiltin("iter"), list);
+    return Py_BuildValue("N(N)", _PyObject_GetBuiltin("iter"), list);
 }
 
 PyDoc_STRVAR(reduce_doc, "Return state information for pickling.");