don't use build_function_type in the Ada FE

don't use build_function_type in the Ada FE
	* gcc-interface/utils.c (def_fn_type): Don't call build_function_type;
	call build_function_type_array or build_varargs_function_type_array
	instead.
	(create_subprog_type): Don't call build_function_type; call
	build_function_type_vec instead.

From-SVN: r173664