title: php set my own timezone based on given GMT offset
body: <p>I've my GMT offset in seconds. I would like to <code>set_default_time_zone()</code> to that GMT offset. What I mean that if I have my GMT offset to 2 hours(7200 seconds) it will set the timezone to GMT+2 if I have 3 hours(10800 seconds) it will set the timezone to GMT+3, how can I do that? the <code>set_default_time_zone()</code> only accept pre-defined timezones strings.</p>