PR gold/12629

	PR gold/12629
	* object.cc (Sized_relobj_file::layout_section): Change shdr
	parameter to be const.
	(Sized_relobj_file::layout_eh_frame_section): New function, broken
	out of do_layout.
	(Sized_relobj_file::do_layout): Defer .eh_frame sections if
	appropriate.  Call layout_eh_frame_section.
	(Sized_relobj_file::do_layout_deferred_sections): Handle .eh_frame
	sections.
	* object.h (class Sized_relobj_file): Update declarations.