Description:
------------
array_diff_uassoc:

    If in both array's of comparison will have some key 0 (zero), the same it is discarded and enclosed as different in the return of 'array_diff_uassoc'.

Reproduce code:
---------------
    function key_compare_func($a, $b)
    {
        if ($a === $b) {
            return 0;
        }
        return ($a > $b)? 1:-1;
    }

    $array1 = array("a" = "green", "b" = "Brown", "c" = "blue", 0 = "red");
    $array2 = array("a" = "green", "b" = "Brown", "c" = "blue", 0 = "red");
    
    $result = array_diff_uassoc($array1, $array2, "key_compare_func");
    print_r($result);

Expected result:
----------------
    Array
    (
    )

Actual result:
--------------
    Array
    (
        [b] = brown
        [c] = blue
        [0] = red
    )