* sunos.c (sunos_slurp_dynamic_symtab): New static function,
broken out of sunos_canonicalize_dynamic_symtab.
(sunos_canonicalize_dynamic_symtab): Call new function
sunos_slurp_dynamic_symtab.
(sunos_add_dynamic_symbols): Add three new parameters. Return the
dynamic symbol table to the caller.
* aoutx.h (aout_link_add_symbols): Permit add_dynamic_symbols
callback to override the symbols being read.
* libaout.h (struct aout_backend_data): Add three new parameters
to add_dynamic_symbols callback.