Reports are in - sixty second shooter runs on Windows, Mac, and Linux. The same cpp code, all platforms. It really does what it says on the tin. I don't even have access to Mac or Linux machines here, so I'm pretty ecstatic that it runs on systems that I haven't even tested. Back in the day, it was a rule of thumb: if you haven't tested your code on that platform, it doesn't work. Times have changed!
One note, though: for now, don't use clock() to do precision timing, there are currently bugs with it. gettimeofday() seems fine.