DR 1558
	* pt.c (dependent_alias_template_spec_p): New.
	(dependent_type_p_r): Handle dependent alias template specialization.
	(template_args_equal): A dependent alias template specializations
	is not equal to its underlying type as a template argument.
	* tree.c (strip_typedefs): Don't strip a dependent alias
	template-id.

From-SVN: r217250