* object.cc (Sized_relobj::layout_section): New function.

	(Sized_relobj::do_layout): Defer layout of input sections until after
	plugin has provided replacement files.
	(Sized_relobj::do_layout_deferred_sections): New function.
	* object.h (Relobj::set_section_offset): Remove virtual keyword.
	(Relobj::layout_deferred_sections): New function.
	(Relobj::do_layout_deferred_sections): New function.
	(Sized_relobj::do_layout_deferred_sections): New function.
	(Sized_relobj::layout_section): New function.
	(Sized_relobj::Deferred_layout): New structure.
	(Sized_relobj::deferred_layout_): New field.
	* plugin.cc (Plugin_manager::finish): Renamed, was cleanup.
	Change all callers.  Layout deferred sections.
	(class Plugin_finish): Renamed, was Plugin_cleanup.  Change all
	references.
	(Plugin_hook::run): Move code from do_plugin_hook inline.
	(Plugin_hook::do_plugin_hook): Remove.
	* plugin.h (Plugin_manager::Plugin_manager): Add missing initializers.
	(Plugin_manager::finish): Renamed, was cleanup.
	(Plugin_manager::should_defer_layout): New function.
	(Plugin_manager::add_deferred_layout_object): New function.
	(Plugin_manager::Deferred_layout_list): New type.
	(Plugin_manager::deferred_layout_objects_): New field.
	(Plugin_hook::do_plugin_hook): Remove.