* elf_file.h: (class Elf_strtab): New class.
gold/:
* gold.cc: (queue_initial_tasks): Pass incremental_inputs to
Incremental_checker.
* incremental.cc: (INCREMENTAL_LINK_VERSION): Change type to
unsigned int.
(class Incremental_inputs_header): New class.
(Incremental_inputs_header_writer): Edit comment.
(Incremental_inputs_entry): New class.
(Incremental_inputs_entry_writer): Edit comment.
(Sized_incremental_binary::do_find_incremental_inputs_section):
Add *strtab_shndx parameter, fill it.
(Sized_incremental_binary::do_check_inputs): New method.
(Incremental_checker::can_incrementally_link_output_file): Use
Sized_incremental_binary::check_inputs.
(Incremental_inputs::report_command_line): Save command line in
command_line_.
* incremental.h:
(Incremental_binary::find_incremental_inputs_section): New
method.
(Incremental_binary::do_find_incremental_inputs_section): Add
strtab_shndx parameter.
(Incremental_binary::do_check_inputs): New pure virtual method.
(Sized_incremental_binary::do_check_inputs): Declare.
(Incremental_checker::Incremental_checker): Add incremental_inputs
parameter, use it to initialize incremental_inputs_.
(Incremental_checker::incremental_inputs_): New field.
(Incremental_checker::command_line): New method.
(Incremental_checker::inputs): New method.
(Incremental_checker::command_line_): New field.
* elfcpp_file.h: Fix header guard. Include <cstdio>.
(class Elf_recognizer): New class, code from gold/object.cc.
(Elf_file::find_section_by_type): New method.
gold/:
* incremental.cc: Include <cstdarg> and "target-select.h".
(vexplain_no_incremental): New function.
(explain_no_incremental): New function.
(Incremental_binary::error): New method.
(Sized_incremental_binary::do_find_incremental_inputs_section): New
method.
(make_sized_incremental_binary): New function.
(open_incremental_binary): New function.
(can_incrementally_link_file): Add checks if output is ELF and has
inputs section.
* incremental.h: Include "elfcpp_file.h" and "output.h".
(Incremental_binary): New class.
(Sized_incremental_binary): New class.
(open_incremental_binary): Declare.
* object.cc (is_elf_object): Use
elfcpp::Elf_recognizer::is_elf_file.
(make_elf_object): Use elfcpp::Elf_recognizer::is_valid_header.
* output.h (Output_file::filesize): New method.
(Elf_file::large_shndx_offset): New function.
(Elf_file::construct): Initialize large_shndx_offset_.
(Elf_File::initialize_shnum): If necessary, adjust shstrndx_ and
set large_shndx_offset_.
