PR 34062 type confusion in elf64_ia64_hash_copy_indirect

The output bfd determines the linker hash table type and symbol entry
type, so the output bfd functions should be used when manipulating
hash table symbols.

	* elflink.c (_bfd_elf_add_default_symbol): Get elf backend data
	from output bfd, not input.
	(elf_link_add_object_symbols): Likewise for e_b_hide_symbol and
	e_b_copy_symbol.
	(_bfd_elf_merge_symbol): Likewise.
	(_bfd_elf_fix_symbol_flags): Likewise.