PR 10931

	* options.h (class General_options): Add --sort-common option.
	* symtab.h (class Symbol_table): Define Sort_commons_order enum.
	* common.cc (Sort_common): Add sort_order parameter to
	constructor.  Add sort_order_ field.
	(Sort_commons::operator): Check sort_order_.
	(Symbol_table::allocate_commons): Determine the sort order.
	(Symbol_table::do_allocate_commons): Add sort_order parameter.
	Change all callers.
	(Symbol_table::do_allocate_commons_list): Likewise.