Fix os/date with nil argument.
@@ -1324,7 +1324,7 @@ JANET_CORE_FN(os_date,
time_t t;
struct tm t_infos;
struct tm *t_info = NULL;
- if (argc) {
+ if (argc && !janet_checktype(argv[0], JANET_NIL)) {
int64_t integer = janet_getinteger64(argv, 0);
t = (time_t) integer;
} else {
