* incremental.cc (Sized_incremental_binary::do_file_has_changed):

	* incremental.cc (Sized_incremental_binary::do_file_has_changed):
	Check disposition for startup file.
	(Incremental_inputs::report_command_line): Ignore
	--incremental-startup-unchanged option.
	* options.cc (General_options::parse_incremental_startup_unchanged):
	New function.
	(General_options::General_options): Initialize new data member.
	* options.h (Incremental_disposition): Add INCREMENTAL_STARTUP.
	(General_options): Add --incremental-startup-unchanged option.
	(General_options::incremental_startup_disposition): New function.
	(General_options::incremental_startup_disposition_): New data member.