[plt-scheme] problem running clock example for FrTime

> I'm not sure why match doesn't work, but here is code that does....
>
> (require scheme/match)

A Scheme library (like scheme/match) won't work automatically with
FrTime.  If the library can itself be evaluated meaningfully in FrTime
(i.e., it's pure), then it should be possible to use it, but I haven't
looked into making this sort of reuse work seamlessly.

Greg