Introduce PyExc_Exception as the conceptual root class for all exceptions.
diff --git a/Include/pyerrors.h b/Include/pyerrors.h
index ece1f3f..580f6d7 100644
--- a/Include/pyerrors.h
+++ b/Include/pyerrors.h
@@ -53,6 +53,7 @@
 
 /* Predefined exceptions */
 
+extern DL_IMPORT(PyObject *) PyExc_Exception;
 extern DL_IMPORT(PyObject *) PyExc_StandardError;
 extern DL_IMPORT(PyObject *) PyExc_NumberError;
 extern DL_IMPORT(PyObject *) PyExc_LookupError;