Description:
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When using strtotime($timezone), where $timezone is the timezone abbreviation, it adds negative offsets and subtracts positive offsets to the time.

If you add a date string, e.g. "April 10, 2009 9:20 AM MDT", the same problem occurs.

Reproduce code:
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<?php
 // It is currently 9:55 pm PDT. Default time zone is PDT.
 echo date('g:i a', strtotime('HADT')) . " \n";
 echo date('g:i a', strtotime('AKDT')) . " \n";
 echo date('g:i a', strtotime('PDT')) . " \n"; // This is the only correct one.
 echo date('g:i a', strtotime('MDT')) . " \n";
 echo date('g:i a', strtotime('CDT')) . " \n";
 echo date('g:i a', strtotime('EDT')) . " \n";
?>

Expected result:
----------------
7:55 pm
8:55 pm
9:55 pm
10:55 pm
11:55 pm
12:55 am

Actual result:
--------------
11:55 pm
10:55 pm
9:55 pm
8:55 pm
7:55 pm
6:55 pm