* symfile.c: #include "gdb_assert.h".

(syms_from_objfile): Add the ability to pass in a section offset
table directly, as an alternative to the section_addr_info table.
Document arguments better.
(symbol_file_add): Pass extra arguments to syms_from_objfile.
* symfile.h (syms_from_objfile): Update declaration.
* rs6000-nat.c (objfile_symbol_add): Pass new arguments to
syms_from_objfile.
* Makefile.in (symfile.o): List dependency on $(gdb_assert_h).