Description:
------------
When using strict error handling Pager_Sliding will fail because of an undefined $_GET[$this->_urlVar]) in line 882

A simple fix for this would be, to check if it is empty:

if(!empty($_GET[$this->_urlVar])) {
$this->_currentPage = max((int)@$_GET[$this->_urlVar], 1);
}




Reproduce code:
---------------
<?
require_once 'PEAR.php';
require_once('Pager/Sliding.php');
error_reporting(E_ALL);

function php_error_handler($errno, $errstr, $errfile, $errline)  {
      echo "<b>$errfile ($errline)</b><br>$errstr";
      exit();
}
set_error_handler('php_error_handler');

$params['totalItems'] = 10;
$params['perPage']    = 10;

$pager = &new Pager_Sliding($params);
$links = $pager->getLinks();
print_r($links);
?>

Expected result:
----------------
Array
(
    [0] => 
    [1] => 
    [2] => 
    [3] => 
    [4] => 
    [5] => 
    [back] => 
    [pages] => 
    [next] => 
    [first] => 
    [last] => 
    [all] => 
)

Actual result:
--------------
/usr/lib/php/Pager/Sliding.php (882)
Undefined index: pageID