Merge branch 'PHP-5.6' into PHP-7.0

* PHP-5.6:
  Fixed bug #73418 Integer Overflow in "_php_imap_mail" leads to crash
  Fix #72696: imagefilltoborder stackoverflow on truecolor images
  Fix #72482: Ilegal write/read access caused by gdImageAALine overflow
  Fix bug #73144 and bug #73341 - remove extra dtor
  Fix bug #73331 - do not try to serialize/unserialize objects wddx can not handle

Author: weltling