decl.c (push_namespace): Namespaces have type void.

	* decl.c (push_namespace): Namespaces have type void.
	* typeck2.c (incomplete_type_error): Complain about namespace
	used as expression.
	* typeck.c (decay_conversion): Likewise.
	* error.c (dump_expr): Support namespaces.

From-SVN: r20035