Description:
------------
The following script causes memory corruption when run from the command line like:

php -f ./bug.php

There are variants of the script that show the bug when run from the web browser, but these scripts are bigger.
Even small changes in the sample script hide the bug.
Notice that several bytes in the output string get overwritten.


Reproduce code:
---------------
<?
class database
{
}

$a = new database;
$b = new database;

class broken
{
	public function __construct ()
	{
	}

	public function __destruct ()
	{
		$this->show (array (
			"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
			"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
			"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
			"", "", "", "", "", "", "", "", "", "", "", "", "", ""
		));
	}
	
	private function show ($values)
	{
		$values_string = "";
		foreach ($values as $val) {
			$values_string .= $val;
		}
		printf ("%s\n", $values_string);
	}
}

$brk = new broken ();
?>


Expected result:
----------------
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

Actual result:
--------------
aaaaaaaaaaaa???aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa