os.EX_USAGE and friends not available in Windows?

[Rush Manbert]

I'm writing scripts that run on Mac OS X and Windows. For automated
testing purposes, I wanted to standardize my exit codes, so discovered
that the Unix sysexit codes were available from the posix module as
os.EX_*.

I changed things around on the Mac, then tested on Windows and the
constants don't seem to be available there. Have I missed something?

Thanks,
Rush