Description:
------------
When combining the use of preg_replace_callback with the __call automagic function, the value returned to the automagic __call function differs from the expected value. It's always wrapped in a single-element single-dimensional array (from what I can tell).

The example code with varied results can describe what I mean perfectly.

This happens in 5.2.6 and 5.2.8 (I just downloaded the latest version before testing this bug to be sure).

Reproduce code:
---------------
<?php
class my {
	function doit(){
		preg_replace_callback("/(.+)/", "var_dump", "aa");
		preg_replace_callback("/(.+)/", array($this, "output"), "aa");
		preg_replace_callback("/(.+)/", array($this, "somefunc"), "aa");
	}

	function output($arg){
		var_dump($arg);
	}

	function __call($func, $arg){
		var_dump($arg);
	}
}
$obj = new my();
$obj->doit();
?>

Expected result:
----------------
array(2) {
  [0]=>
  string(2) "aa"
  [1]=>
  string(2) "aa"
}
array(2) {
  [0]=>
  string(2) "aa"
  [1]=>
  string(2) "aa"
}
array(2) {
  [0]=>
  string(2) "aa"
  [1]=>
  string(2) "aa"
}

Actual result:
--------------
array(2) {
  [0]=>
  string(2) "aa"
  [1]=>
  string(2) "aa"
}
array(2) {
  [0]=>
  string(2) "aa"
  [1]=>
  string(2) "aa"
}
array(1) {
  [0]=>
  array(2) {
    [0]=>
    string(2) "aa"
    [1]=>
    string(2) "aa"
  }
}