PowerPC64 ELFv2 support for gold.

PowerPC64 ELFv2 support for gold.

elfcpp/
	* powerpc.h (EF_PPC64_ABI): New enum constant.
	(STO_PPC64_LOCAL_BIT, STO_PPC64_LOCAL_MASK): Likewise.
	(ppc64_decode_local_entry): New function.
	(ppc64_encode_local_entry): Likewise.
gold/
	* powerpc.cc (Powerpc_relobj::abiversion, set_abiversion,
	ppc64_local_entry_offset, ppc64_local_entry_offset,
	do_read_symbols): New functions.
	(Powerpc_relobj::e_flags_, st_other_): New vars.
	(Powerpc_relobj::Powerpc_relobj): Call set_abiversion.
	(Powerpc_dynobj::abiversion, set_abiversion): New functions.
	(Powerpc_relobj::e_flags_): New var.
	(Target_powerpc::first_plt_entry_offset, plt_entry_size): Inline
	and adjust for ELFv2.
	(Target_powerpc::abiversion, set_abiversion, stk_toc): New functions.
	(Powerpc_relobj::do_find_special_sections): Check no .opd in ELFv2.
	(Powerpc_dynobj::do_find_special_sections): Likewise.
	(Target_powerpc::do_define_standard_symbols): Define ".TOC.".
	(Target_powerpc::Branch_info::make_stub): Adjust stub destination
	to ELFv2 local entry.
	(Target_powerpc::do_relax): No thread safe barriers needed for
	ELFv2.
	(Output_data_plt_powerpc::initial_plt_entry_size_,
	plt_entry_size): Delete.  Replace all uses with
	first_plt_entry_offset() and plt_entry_size().
	(Output_data_plt_powerpc::Output_data_plt_powerpc): Remove
	reserved_size parm.  Update callers.
	(Output_data_plt_powerpc::entry_count): Update.
	(Output_data_plt_powerpc::first_plt_entry_offset): Make private
	and use Target_powerpc::first_plt_entry_offset().
	(Output_data_plt_powerpc::get_plt_entry_size): Similarly and
	rename to plt_entry_size.
	(Output_data_plt_powerpc::add_ifunc_entry,
	add_local_ifunc_entry): Adjust reloc for ELFv2.
	(glink_eh_frame_fde_64): Rename to glink_eh_frame_fde_64v1.
	(glink_eh_frame_fde_64v2): New.
	(Stub_table::plt_call_size): Support ELFv2 sizing.
	(Output_data_glink::add_eh_frame): Use the new FDE.
	(Output_data_glink::set_final_data_size): Adjust for ELFv2 glink.
	(Stub_table::do_write): Write ELFv2 stubs and glink.
	(Target_powerpc::Relocate::relocate): Replaces nop after call
	with ld 2,24(1) and adjust local offset destination for ELFv2.