[rfa] Deprecate msymbol.info, add msymbol.bfd_symbol?

[Andrew Cagney <ac131313@redhat.com>]

There isn't yet a patch yet.  I wan't to run the theory past people, 
especially the symtab maintainers.

A recent thread discussed the "info" field of the symbol table where 
MichaelC was trying to pack it down, while I was arguing that it should 
"just go", instead have the computation performed by 
MAKE_MSYMBOL_SPECIAL on every minimal-symbol performed on-demand (and 
after the symbo-table load).

The problem with eliminating "info" is that it would leave the on-demand 
code with no efficient way to find the underlying BFD info that it 
needes :-(

Consequently, I'd like to propose that "info" be superseeded by a 
"struct bfd_symbol *" pointer.

I say "superseed" as I'd prefer doing this in two steps.  In addition to 
the per-architecture MAKE_MSYMBOL_SPECIAL, readers like elfread.c also 
squirrel away info in that field :-/

The consequence will be that, for a time, the minimal symbol table will 
be bigger.  Since its the minimal-symbol table I don't feel too guilty, 
long term the minimal-symbol's size will be restored.  In fact, given 
the apparent overlap between bfd_symbol and general_symbol_info (name, 
section, bfd_section, ?), it opens the way to further savings.

thoughts? does the theory look correct?
Andrew