Gentoo use flags for running Drupal

I moved my Drupal web server from Ubuntu to Gentoo.
It was quite a bear getting the correct use flags set for Drupal.

The following are the use flags that you need for Drupal to work properly:

apache2 cli cgi gd session sockets pcre php postgres xml xmlrpc xsl

* Note: you might not need xmlrpc or xsl, but I was getting pretty tired of recompiling.