PR 10980

	PR 10980
	* options.cc (General_options::parse_section_start): New function.
	(General_options::section_start): New function.
	(General_options::General_options): Initialize all members.
	* options.h: Include <map>
	(class General_options): Add --section-start.  Add section_starts_
	member.
	* layout.cc (Layout::attach_allocated_section_to_segment): If
	--section-start was used, set the address of the segment.  Remove
	local sort_sections.
	(Layout::relaxation_loop_body): If the address of the load segment
	has been set by --section-start, don't use it.
	* output.h (Output_segment::update_flags_for_output_section): New
	function.
	* output.cc (Output_segment::add_output_section): Call
	update_flags_for_output_section.