The localtime function takes a time_t* argument. Passing
the ut_time member of the utmp struct as this argument
doesn't work on 64 bit systems because the lengths of the
arguments don't agree. So use a temproary variable to
store the ut_time value in a time_t variable and pass
the address of the time_t variable to localtime.
Signed-off-by: Clark Rawlins <clark@bit63.org>