diff --git a/Include/stringobject.h b/Include/stringobject.h
index 9049455..2a56ef6 100644
--- a/Include/stringobject.h
+++ b/Include/stringobject.h
@@ -39,6 +39,7 @@
     char ob_sval[1];
 } PyStringObject;
 
+extern DL_IMPORT(PyTypeObject) PyBaseString_Type;
 extern DL_IMPORT(PyTypeObject) PyString_Type;
 
 #define PyString_Check(op) PyObject_TypeCheck(op, &PyString_Type)