eprintf for darwin, as committed

[Benjamin Kosnik]

> This is the version I'll commit.  I renamed the .ver file, following
> Benjamin's suggestion, although I'm not really sure about it---I can't
> think of any reasonable reason to have anything other than eprintf in
> this file.

Thanks.

For this port, at this time, eprintf.ver might be sufficient. I'm
thinking about other ports using this same naming convention, with
their own port-specific symbols. Some kind of consistency would be
helpful.

Specifically, I'm thinking now is the time to get the arm-eabi stuff
properly moved into something like this.

-benjamin