Description:
------------
There is a segmentation fault when I try to call intercept_add and set its target.


Reproduce code:
---------------
<?php
function foo() {

    return 20 + 20;
}

function trigger() {

 echo "Triggering it :)\n\n";
}

intercept_add("foo","trigger");
foo();
?>


Actual result:
--------------
#php example.php 
Triggering it :)

Segmentation fault