bfd/

bfd/
	PR 5604
	* elf-bfd.h (struct elf_backend_data): Add gc_keep.  Remove param
	names from others.
	(_bfd_elf_gc_keep): Declare.
	* elfxx-target.h (elf_backend_gc_keep): Define.
	(elfNN_bed): Init new field.
	* elflink.c (_bfd_elf_gc_keep): New function.
	(bfd_elf_gc_sections): Call gc_keep.
	* elf64-ppc.c (elf_backend_gc_keep): Define.
	(struct _ppc64_elf_section_data): Move .opd related fields to
	a struct so they don't occupy the same storage.  Adjust accesses
	throughout file.
	(ppc64_elf_gc_keep): New function, split out from..
	(ppc64_elf_gc_mark_hook): ..here.  Don't call _bfd_elf_gc_mark
	to mark .opd section, just set gc_mark.
	(ppc64_elf_edit_opd): Remove no_opd_opt parm.  Don't set opd->adjust
	unless we are changing .opd.  Test non-NULL opd->adjust at all
	accesses throughout file.
	* elf64-ppc.h (ppc64_elf_edit_opd): Update prototype.
ld/
	PR 5604
	* ldlang.c (lang_gc_sections): Move code to set SEC_KEEP on entry
	syms to _bfd_elf_gc_keep.
	* emultempl/ppc64elf.em (ppc_before_allocation): Don't call
	ppc64_elf_edit_opd if no_opd_opt.