pr: -e not recognized

`pr` does not recognize `-e` option:

```sh
> echo "a\tb" | pr -e5 
error: unexpected argument '-e' found

tip: to pass '-e' as a value, use '-- -e'

Usage: pr [OPTION]... [FILE]...

For more information, try '--help'.
```

The original GNU `pr` correctly recognizes it:

```sh
> echo "a\tb" | gnupr -e5
[...]
a    b
```
