This form delegates the knowledge of the time zone
information to an external compiled zoneinfo file
(à la BSD).
Caveat: Each time the gettimeofday()
function is called, the external zone info is read in
again (at least on some SVR4 systems). That results in
three wasted system calls with every apache request
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 7944)=778