title: Get timezone offset in PHP given a unix timestamp
body: <p>I have a Unix timestamp that comes from a database that is (unfortunately) in a timezone with a certain of either +3600 or +7200, depending on if it's DST or not. This has never been a problem before, but our website is currently moving to a more international audience and because of Javascript interaction with said timestamps, I need to convert the timestamp without any offset.</p>
  
  <p>So, how do I, given just a Unix timestamp, get the offset for the timezone, at the moment of that timestamp? I'm looking through the PHP docs, but there's so many date/time functions I'm a bit lost.</p>
  
  <p>I'm using PHP 5.2.3</p>