Handle output sections with more than 0x7fffffff bytes.

	Handle output sections with more than 0x7fffffff bytes.
	* object.h (class Relobj): Change map_to_output_ to
	output_sections_, and just keep a section pointer.  Change all
	uses.  Move comdat group support to Sized_relobj.
	(Relobj::is_section_specially_mapped): Remove.
	(Relobj::output_section): Remove poff parameter.  Change all
	callers.
	(Relobj::output_section_offset): New function.
	(Relobj::set_section_offset): Rewrite.
	(Relobj::map_to_output): Remove.
	(Relobj::output_sections): New function.
	(Relobj::do_output_section_offset): New pure virtual function.
	(Relobj::do_set_section_offset): Likewise.
	(class Sized_relobj): Add section_offsets_ field.  Add comdat
	group support from Relobj.  Update declarations.
	(Sized_relobj::get_output_section_offset): New function.
	(Sized_relobj::do_output_section_offset): New function.
	(Sized_relobj::do_set_section_offset): New function.
	* object.cc (Relobj::output_section_address): Remove.
	(Sized_relobj::Sized_relobj): Initialize new fields.
	(Sized_relobj::include_section_group): Cast find_kept_object to
	Sized_relobj.
	(Sized_relobj::include_linkonce_section): Likewise.
	(Sized_relobj::do_layout): Use separate arrays for output section
	and output offset.
	(Sized_relobj::do_count_local_symbols): Change map_to_output to
	output_sections.
	(Sized_relobj::do_finalize_local_symbols): Change map_to_output to
	output_sections and section_offsets.
	(Sized_relobj::write_local_symbols): Likewise.
	(map_to_kept_section): Compute output address directly.
	* reloc.cc (Sized_relobj::do_read_relocs): Change map_to_output to
	output_sections and section_offsets.
	(Sized_relobj::write_sections): Likewise.
	(Sized_relobj::relocate_sections): Likewise.
	* symtab.cc (sized_finalize_symbol): Use output_section_offset.
	* output.h (class Output_reloc): Update declarations.  Change
	u2_.relobj to Sized_relobj*.
	(class Output_data_reloc): Change add functions to use
	Sized_relobj*.
	* output.cc (Output_reloc::Output_reloc): Change relobj to
	Sized_relobj*.
	(Output_reloc::local_section_offset): Change return type to
	Elf_Addr.  Use get_output_section_offset.
	(Output_reloc::get_address): Likewise.
	(Output_section::is_input_address_mapped): Don't call
	is_section_specially_mapped.
	(Output_section::output_offset): Likewise.
	(Output_section::output_address): Likewise.
	(Output_section::starting_output_address): Likewise.
	* copy-relocs.cc (Copy_relocs::copy_reloc): Change object
	parameter to Sized_relobj*.
	(Copy_relocs::need_copy_reloc): Likewise.
	(Copy_relocs::save): Likewise.
	* copy-relocs.h (class Copy_relocs): Update declarations.
	(class Copy_relocs::Copy_reloc_entry): Change constructor to use
	Sized_relobj*.  Change relobj_ field to Sized_relobj*.
	* target-reloc.h (relocate_for_relocatable): Change
	offset_in_output_section type to Elf_Addr.  Change code that uses
	it as well.
	* layout.cc (Layout::layout): Always set *off.
	* mapfile.cc (Mapfile::print_input_section): Use
	output_section_offset.
	* i386.cc (Target_i386::copy_reloc): Change object parameter to
	Sized_relobj*.
	* powerpc.cc (Target_powerpc::copy_reloc): Likewise.
	* sparc.cc (Target_sparc::copy_reloc): Likewise.
	* x86_64.cc (Target_x86_64::copy_reloc): Likewise.