CF is belied to be superior to the strftime-based version. Consider using CF to format date on Windows as well.
I assume the FIXME you refer to is:
static const int yearLen = 5; // FIXME will be a problem in the year 10,000
I agree with this patch in principle. I think the set of tests would be better handled as a "USE(CF)", since that seems to be what the current logic is attempting to do.