As far as I can tell PyEval_GetOwner was removed in 1997 (when it was

Michael W. Hudson · Michael W. Hudson · commit 2aec8b744e2a · 2003-02-20T17:59:17.000Z
called something else!).  I can't imagine removing the prototype is
going to hurt, but put it back if *you* can.
diff --git a/Include/ceval.h b/Include/ceval.h
@@ -30,7 +30,6 @@ struct _frame; /* Avoid including frameobject.h */
 PyAPI_FUNC(PyObject *) PyEval_GetBuiltins(void);
 PyAPI_FUNC(PyObject *) PyEval_GetGlobals(void);
 PyAPI_FUNC(PyObject *) PyEval_GetLocals(void);
-PyAPI_FUNC(PyObject *) PyEval_GetOwner(void);
 PyAPI_FUNC(struct _frame *) PyEval_GetFrame(void);
 PyAPI_FUNC(int) PyEval_GetRestricted(void);
 
