You can enable this module by creating a symbolic
link from ${PREFIX}/conf/php5.sample/apc.ini to
${PREFIX}/conf/php5/apc.ini.

ln -fs ${PREFIX}/conf/php5.sample/apc.ini \
        ${PREFIX}/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 ${PREFIX}/pecl-APC/INSTALL
for details.