Added in 1.9.0
Returns the local timezone setting in seconds. Positive is West/Earlier than UTC, negative is East/Later than UTC.
Returns your local timezone relative to UTC in seconds, adjusted by $daylight.
Positive is west/earlier than UTC zone, negative is east/later than UTC.
Total of $timezone + $daylight is always the same while your time zone settings are not changed.
During winter, New York City has $timezone = 18000 $daylight = 0.
During summer, these values change to $timezone = 14400 $daylight = 3600
//echo -a $gmt is the same as $calc($ctime + $timezone) year round (except for low gmt values requiring ctime be negative)