Issue #1066: implement PEP 3109, 2/3 of PEP 3134.
diff --git a/Lib/wsgiref/handlers.py b/Lib/wsgiref/handlers.py
index d9347e5..8231620 100644
--- a/Lib/wsgiref/handlers.py
+++ b/Lib/wsgiref/handlers.py
@@ -151,7 +151,7 @@
             try:
                 if self.headers_sent:
                     # Re-raise original exception if headers sent
-                    raise exc_info[0], exc_info[1], exc_info[2]
+                    raise exc_info[0](exc_info[1]).with_traceback(exc_info[2])
             finally:
                 exc_info = None        # avoid dangling circular ref
         elif self.headers is not None: