Hack around toUnicode on MacOS.

Basically, the thing takes in the null string and calls some convert to
unicode bullshit on it that can fail.  I should probably patch this out.
Backed out changeset 36f289a1f951

The hack doesn't work, sadly.  I'll have to actually fix the problem (oh no!).
Actually fix the problem.

The author didn't seem to know about the unicode() builtin.  I should consider
submitting a pull request to fix this.