Issue #14288: Serialization support for builtin iterators.
diff --git a/Include/iterobject.h b/Include/iterobject.h
index f61726f..86abb25 100644
--- a/Include/iterobject.h
+++ b/Include/iterobject.h
@@ -18,6 +18,8 @@
 
 PyAPI_FUNC(PyObject *) PyCallIter_New(PyObject *, PyObject *);
 
+PyAPI_FUNC(PyObject *) _PyIter_GetBuiltin(const char *iter);
+
 #ifdef __cplusplus
 }
 #endif