Upgrade PHP PECL alternative PHP cache extension (apc) to version 3.0.19
to fix arbitrary code execution problems (CVE-2008-1488).

Changes since 3.0.16:
* Fix for CVE-2008-1488.
* Fix apc_add() cache expunge bug.
* Added parameter to apc_fetch to determine success/failure when fetching
  booleans.
* Fix for bug 13504.
* Move expunge callback groundwork to 3.1 (Rasmus)
* Fix fd-leak.
* Fix double-free on builtin functions.
* Initial PHP 5.3 support.

(tonnerre)