Issue 1294232: Fix errors in metaclass calculation affecting some cases of metaclass inheritance. Patch by Daniel Urban.
diff --git a/Include/object.h b/Include/object.h
index 3753785..2528841 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -449,6 +449,7 @@
#ifndef Py_LIMITED_API
PyAPI_FUNC(PyObject *) _PyType_Lookup(PyTypeObject *, PyObject *);
PyAPI_FUNC(PyObject *) _PyObject_LookupSpecial(PyObject *, char *, PyObject **);
+PyAPI_FUNC(PyTypeObject *) _PyType_CalculateMetaclass(PyTypeObject *, PyObject *);
#endif
PyAPI_FUNC(unsigned int) PyType_ClearCache(void);
PyAPI_FUNC(void) PyType_Modified(PyTypeObject *);