* incremental.cc (Sized_incremental_binary::setup_readers): Allocate

	* incremental.cc (Sized_incremental_binary::setup_readers): Allocate
	global symbol map.
	(Sized_incremental_binary::do_apply_incremental_relocs): New function.
	(Sized_incr_relobj::do_add_symbols): Add symbols to global symbol map.
	(Sized_incr_relobj::do_relocate): Remap section indices in incremental
	relocations.
	(Sized_incr_dynobj::do_add_symbols): Add symbols to global symbol map.
	(Sized_incr_dynobj::do_for_all_global_symbols): Remove FIXME.
	(Sized_incr_dynobj::do_for_all_local_got_entries): Likewise.
	* incremental.h
	(Incremental_inputs_reader::global_symbol_reader_at_offset): New
	function.
	(Incremental_binary::apply_incremental_relocs): New function.
	(Incremental_binary::do_apply_incremental_relocs): New function.
	(Sized_incremental_binary::Sized_incremental_binary): Initialize new
	data member.
	(Sized_incremental_binary::add_global_symbol): New function.
	(Sized_incremental_binary::global_symbol): New function.
	(Sized_incremental_binary::do_apply_incremental_relocs): New function.
	(Sized_incremental_binary::symbol_map_): New data member.
	* layout.cc (Layout_task_runner::run): Apply incremental relocations.
	* target.h (Sized_target::apply_relocation): New function.
	* target-reloc.h (apply_relocation): New function.
	* x86_64.cc (Target_x86_64::apply_relocation): New function.