* pt.c (maybe_process_partial_specialization): Complain about
	specialization in wrong namespace.
	* tree.c (decl_namespace_context): New fn.
g++.pt/explicit73.C
	* decl2.c (arg_assoc_type): Handle TEMPLATE_TEMPLATE_PARM.
	* pt.c (coerce_template_template_parms): Handle nested
	template template parameters.
g++.pt/nttp[12].C

From-SVN: r25072