[llvm] r185726 - Add a createUniqueFile function and switch llvm's users of unique_file.

[Rafael Espíndola]

> This regressed the Object/nm-archive test. We need to anchor on the output
> file to make sure we can actually write the temporary file.
>
> Fixed in r185825.


Yes, thanks a lot. The uniquely named file has to be in the same
directory as the one we will rename it too.

Cheers,
Rafael