Hello,

This converts the m68hc11 to the return_value architecture method 
allowing us to delete RETURN_VALUE_ON_STACK.  In doing this I assumed 
that m68hc11 ABI didn't guarentee that a struct-return address wasn't 
preserved across a function call and, hence, deleted the 
EXTRACT_STRUCT_VALUE_ADDRESS logic.

Stephane, does the m68hc11 change look ok?
Andrew