> Richard:  Can you clarify what's meant by "packed enums"?  Is it what GCC
> gives you if you define DEFAULT_SHORT_ENUMS?

Yes, I believe so.  But I need to do some checking that what this gives is 
what the ABI mandates.  I can't do that until I get back to work in 
January.  In the mean-time I think it would be worth building a set of 
libraries with this enabled to see if it breaks as has been suggested.

R.