Add "exceptions" to list of built-in modules for the sake of
sys.builtin_module_names.  (Noticed by Toby Dickenson.)

[Tim, please test!]
diff --git a/PC/config.c b/PC/config.c
index f85415d..d9d9187 100644
--- a/PC/config.c
+++ b/PC/config.c
@@ -117,6 +117,7 @@
         {"__main__", NULL},
         {"__builtin__", NULL},
         {"sys", NULL},
+	{"exceptions", NULL},
 
         /* Sentinel */
         {0, 0}