check_once_cc_ccache_set_kdc_time_offset
check_once_cc_ccache_set_kdc_time_offset(ccache, cc_credentials_v5, 0, ccNoError, "first time setting offset (v5)");
cc_int32 check_once_cc_ccache_set_kdc_time_offset(cc_ccache_t ccache, cc_int32 credentials_version, cc_time_t time_offset, cc_int32 expected_err, const char *description);