Hello,

Here is a new version of the patch implementing Tom's idea of
flagging size-less minimal symbols... On platforms where he size
isn't set, i's a bit of a give-and-take, fixing the problem reported,
at the cost of finding some symbols that we were previously fitering
out (by luck or accident). I think it's for the best.

gdb/ChangeLog:

        * symtab.h (struct minimal_symbol) [has_size]: New field.
        (MSYMBOL_SIZE): Adjust to forbid macro from being used as lvalue.
        (SET_MSYMBOL_SIZE, MSYMBOL_HAS_SIZE): New macros.
        * printcmd.c (build_address_symbolic): Only filter out zero-sized
        minimal symbols if the symbol's size is actually known.
        * minsyms.c (prim_record_minimal_symbol_full): Adjust setting
        of msymbol's size field.  Add comment.
        (install_minimal_symbols): Use SET_MSYMBOL_SIZE to set the
        minimal symbol size.
        * elfread.c (elf_symtab_read, elf_rel_plt_read): Use
        SET_MSYMBOL_SIZE to set the minimal symbol size.

Tested on all of AdaCore's supported platforms via our testsuite.
Also tested on x86_64-linux using the official testsuite.

OK to commit?

Thanks,
-- 
Joel