* output.h (Output_segment::set_section_addresses): Pass increase_relro

	* output.h (Output_segment::set_section_addresses): Pass increase_relro
	by reference; adjust all callers.
	* output.cc (Output_segment::set_section_addresses): Adjust references
	to increase_relro. Add padding to *increase_relro when ORDER_RELRO_LAST
	list is empty.
	(Output_segment::set_offset): Assert if PT_GNU_RELRO segment does not
	end at page boundary.