* elf-bfd.h (struct elf_link_hash_entry): Delete dynamic_weak.
	Add ref_dynamic_nonweak.
	* elflink.c (_bfd_elf_mark_dynamic_def_weak): Delete.
	(_bfd_elf_merge_symbol): Don't call above function.  Move
	setting of ref_dynamic_nonweak and dynamic_def earlier.  Don't
	clear dynamic_def.
	(elf_link_add_object_symbols): Delete redundant "override" test.
	Don't set dynamic_def here.
	(elf_link_output_extsym): Update.