Minor internal code tweaks

* mark all eligible classes Final
* new TableIndex strong type
* buildfixes for HAVE_DEBUGSPEW()
* overridden virtual destructors tagged as such

1 files changed, 1 insertions, 1 deletions

diff --git a/src/lanes.cpp b/src/lanes.cpp
index 87f9a90..678540d 100644
--- a/src/lanes.cpp
+++ b/src/lanes.cpp
@@ -286,7 +286,7 @@ LUAG_FUNC(lane_new)
         raise_luaL_error(L_, "could not create lane: out of memory");
     }
 
-    class OnExit
+    class OnExit final
     {
         private:
         lua_State* const L;