Fix compilation error on Windows

[tomaka]

Introduced in #87

Better continuous integration would be great. It's the second time in three days that one of the official crates doesn't compile on Windows.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @alexcrichton (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. The way Github handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see CONTRIBUTING.md for more information.

[alexcrichton]

Do you know if it's possible to enable continuous integration for windows? We'd love to support it, we just don't know where to find it other than hosting it ourselves :(

[alexcrichton]

Thanks though!

[tomaka]

I'm using appveyor.
See for example what I do for glutin.

[tomaka]

It works great, the only problem is that there's a ~10-15mn wait in the queue.