Standard div/2 integer function and operator are missing

The standard div/2 integer function and operator are missing

```text
?- X is 7 div 2.
{SYNTAX ERROR: (lns 74-74) operator expected after expression
X is 7
** here **
div 2 .
}
?- X is div(7,2).
{ERROR: arithmetic:is/2, arg 2 - expected an arithmetically evaluable expression, found div(7,2)}

aborted
```