This code:
<?php

$now = date('r');
$stamp = strtotime($now);
$conv = date('r', $stamp);

echo "$now\n$conv";

?>

produces this output:
Thu, 29 Nov 2001 15:24:21 +0100
Sun, 25 Nov 2001 12:24:21 +0100

This is the fix:
--- parsedate.y~        Thu Nov 15 15:33:41 2001
+++ parsedate.y Thu Nov 29 15:28:52 2001
@@ -255,7 +255,7 @@
            yySeconds = $5;
            yyMeridian = MER24;
            yyHaveZone++;
-               if ($6 < -100 || $6 > 100) {
+               if ($6 <= -100 || $6 >= 100) {
                        yyTimezone =  -$6 % 100 + (-$6 / 100) * 60;
                } else {
                        yyTimezone =  -$6 * 60;