On UNIX-like systems don't fail because winerror is not available

Author: StanHatko

Lib/asyncio/windows_events.py

@@ -558,7 +558,8 @@ def finish_accept(trans, key, ov):
             except OSError as exc:
                 # Fix bug when accepting a socket connection and ERROR_NETNAME_DELETED
                 # occurs, leads this into a closing of the serving socket.
-                if exc.winerror in (_overlapped.ERROR_NETNAME_DELETED,
+                if hasattr(exc, 'winerror') and exc.winerror in (
+                                    _overlapped.ERROR_NETNAME_DELETED,
                                     _overlapped.ERROR_OPERATION_ABORTED):
                     conn.close()
                     raise ConnectionResetError(*exc.args)