* gold.cc (queue_middle_tasks): Move detect_odr_violations..

	* gold.cc (queue_middle_tasks): Move detect_odr_violations..
	* layout.cc (Layout_task_runner::run): ..to here.
	* symtab.h (struct Symbol_location): Extract from..
	(class Symbol_table): ..here.
	* symtab.cc (Symbol_table::linenos_from_loc): Invoke function_location.
	* target.h (class Target): Add function_location and
	do_function_location functions.
	(class Sized_target): Add do_function_location.
	* object.h (class Sized_relobj_file): Move find_shdr..
	(class Object): ..to here.
	* object.cc: Likewise.  Update to suit.  Instantiate.
	(Sized_relobj_file::find_eh_frame): Update find_shdr call.
	* powerpc.cc (class Powerpc_dynobj): New.
	(Target_powerpc::do_function_location): New function.
	(Powerpc_relobj::do_find_special_sections): Update find_shdr call.
	(Powerpc_dynobj::do_read_symbols): New function.
	(Target_powerpc::do_make_elf_object): Make a Powerpc_dynobj.