[m-rev.] diff: private_builtin should not import io, step 2

[Julien Fischer]

On Tue, 9 Dec 2014, Zoltan Somogyi wrote:

> The diff itself is straightforward, and the concept has already
> been reviewed, so there is no need for a review. However,
> I cannot commit this until everyone has installed a compiler
> which includes step 1, which was committed yesterday morning.
>
> Can people please email me when they have done so?

I have installed the compiler with step 1.  rotd-2014-12-08 includes
the change as well.

Cheers,
Julien.