Merge of descr-branch back into trunk.
diff --git a/Modules/Setup.dist b/Modules/Setup.dist
index 9114414..e9c2a94 100644
--- a/Modules/Setup.dist
+++ b/Modules/Setup.dist
@@ -464,3 +464,5 @@
 # Example -- included for reference only:
 # xx xxmodule.c
 
+# Another example -- the 'xxsubtype' module shows C-level subtyping in action
+xxsubtype xxsubtype.c