fails:Array#pack with format 'P' round-trips a string through pack and unpack
fails:Array#pack with format 'P' with nil gives a null pointer
fails:Array#pack with format 'p' round-trips a string through pack and unpack
fails:Array#pack with format 'p' with nil gives a null pointer
fails:Array#pack with format 'P' produces as many bytes as there are in a pointer
fails:Array#pack with format 'p' produces as many bytes as there are in a pointer
