implement chained exception tracebacks
patch from Antoine Pitrou #3112
diff --git a/Include/traceback.h b/Include/traceback.h
index b77cc92..0be3ad5 100644
--- a/Include/traceback.h
+++ b/Include/traceback.h
@@ -19,7 +19,7 @@
PyAPI_FUNC(int) PyTraceBack_Here(struct _frame *);
PyAPI_FUNC(int) PyTraceBack_Print(PyObject *, PyObject *);
-PyAPI_FUNC(int) Py_DisplaySourceLine(PyObject *, const char *, int);
+PyAPI_FUNC(int) Py_DisplaySourceLine(PyObject *, const char *, int, int);
/* Reveal traceback type so we can typecheck traceback objects */
PyAPI_DATA(PyTypeObject) PyTraceBack_Type;