Mac has gettimeofday defined, but cmsys wasn't aware of that, so it was falling back to using time() which only provides second resolution.  Fixed to allow usec res.
Mac has gettimeofday defined, but cmsys wasn't aware of that, so it was falling back to using time() which only provides second resolution.  Fixed to allow usec res.

chuckatkins/KWSys,chuckatkins/KWSys,chuckatkins/KWSys,chuckatkins/KWSys