Description:
------------
Hello!

I have found 4 possible security issues.
Can you fix it to make a more stable PHP version please?

Thank you for your good job!

Test script:
---------------
<?php
    imageaffinematrixget(1, str_repeat('A', 2000));
?>

<?php
    $o = (object) str_repeat(urldecode("%u0c0c%u0c0c"), 2000);
    imageaffinematrixget(2, $o);
?>

<?php
    gmp_testbit(str_repeat("A", 2000), 1);
?>

<?php
    $o = new UConverter(1, 1);
    $o->toUCallback(1, 1, 1, $b);
?>

Actual result:
--------------
A nice crash on Windows 7 x64.