./configure
./configure --with-apxs=/usr/sbin/apxs --without-pic \
            --with-config-file-scan-dir=/etc/php
include_path
include_path = "/usr/share/pear:."
<?php
    include './template_helpers.inc';
    include 'business_logic.inc';
?>
open_basedir
open_basedir = "/usr/share/htdocs/:/usr/share/pear/"
open_basedir checking adds some extra syscalls to every file operation. It can be useful, but it is rather expensive, so turn it off if you don't you need it.

variables_order
variables_order = "GPC"
<?php
    echo $_SERVER['DOCUMENT_ROOT'];
    echo getenv('DOCUMENT_ROOT'); 
?>