You can enable this module by creating a symbolic
link from /var/www/conf/php5.sample/apc.ini to
/var/www/conf/php5/apc.ini.

ln -fs /var/www/conf/php5.sample/apc.ini \
        /var/www/conf/php5/apc.ini

If you already have Apache running on your machine,
you should not use "apachectl restart" - instead,
you should fully stop and then restart the server.

You'll also need to configure APC using various 
settings in php.ini.  See /var/www/pecl-APC/INSTALL
for details.
