Description:
------------
When I was using function lambda in class, I saw that it is using a lot of operating memory. I saw this error when the script was sending e-mails reports to users registered in my service.

Reproduce code:
---------------
<?php
class example
{
	function test()
	{
		$var = create_function('', '$a = 1;$b=2;$c=$a+$b;');
		$var();
		unset($var);
	}
}
$example = new example;
for($i=0;$i<=10000;$i++)
{
	$example->test();
}

echo 'Results after remove lambda'."\n";
echo 'Memory limit: '.ini_get('memory_limit')."\n";
echo 'Usage: '. round(memory_get_usage()/1024/1024, 1)."\n";
echo 'Peak:'. round(memory_get_peak_usage()/1024/1024, 1);
echo "\n";

?>

Expected result:
----------------
I expected a slight growth of operating memory usage by script. By using endless loop, I expect the script will be executing even for 2 hours, thanks to correction of appropriate php configuration directive.

Actual result:
--------------
When I used endless loop while(true), php engine ended its work after 2 minutes,generating error "PHP Fatal error:  Allowed memory size of 41943040 bytes exhausted (tried to allocate 40961 bytes)"