Using the date selector in kcm_clock to set any date further than February 7, 2106 resulted in setting the time to ((time_t) (unsigned int) -1). This patch makes setting any date further than this to spit out an DateError.
Also, it's a seed for discussion regarding this KCM module as passing the values as QStrings and converting from/to time_t doesn't seem like a manageable solution to the problem.
Thanks for your opinions.