pack.c: raise error for unsupported `w` directive.
@@ -1228,7 +1228,7 @@ alias:
type = PACK_TYPE_STRING;
flags |= PACK_FLAG_WIDTH | PACK_FLAG_COUNT2 | PACK_FLAG_Z;
break;
- case 'p': case 'P':
+ case 'p': case 'P': case 'w':
case '%':
mrb_raisef(mrb, E_ARGUMENT_ERROR, "%c is not supported", (char)t);
break;
