include/

include/
	* bfdlink.h (struct bfd_link_hash_entry): Add u.undef.weak.
bfd/
	* linker.c (_bfd_generic_link_add_one_symbol): Set u.undef.weak.
	* elflink.c (elf_smash_syms): Restore symbols that were undefweak
	before the as-needed lib was loaded.  Abort on unexpected refs.