+ time_t_max = (! time_t_signed
+ ? (time_t) -1
+ : ~ (~ (time_t) 0 << (sizeof (time_t) * CHAR_BIT - 1)));
+ time_t_min = (! time_t_signed
+ ? (time_t) 0
+ : time_t_signed_magnitude
+ ? ~ (time_t) 0
+ : ~ (time_t) 0 << (sizeof (time_t) * CHAR_BIT - 1));