FreeBSD memcache.so error after portupgrade

I got the following error for PHP after recent portupgrade:

PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/local/lib/php/20090626/memcache.so' - /usr/local/lib/php/20090626/memcache.so: Undefined symbol "php_session_create_id" in Unknown on line 0

to fix this all you need to do is reinstall pecl-memcache, like this:

cd /usr/ports/databases/pecl-memcache
make deinstall
make install clean

that should make the problem go away ...