Hello,

Ref: [rfc] Struct return values
http://sources.redhat.com/ml/gdb/2004-01/msg00123.html

This deprecates the existing extract_struct_value_address, clearing the 
way for a replacement such as extract_returned_value_address.

As the comments note, other than the 32-bit SPARC, no ABI has so far 
been identified that allows for the robust implementation of an extract 
struct-convention return-value's address method.  Further, a quick 
glance through the remaining extract methods suggests that they too are 
broken - the're all trying to extract the return-value from a register 
and typical ABIs don't guarentee that the return-value address register 
is preserved across function calls.

The patch also adds a bunch of comments to core-GDB to [hopefully] point 
the way to the required changes needed to make the 32-bit SPARC ABIs 
case work.  I don't have a SPARC handy so MarkK, over to you :-/

Comments?  I'll give this part a week.
Andrew