1.  Make sure you have Caudium installed prior to attempting to
    install PHP 4. For PHP 4 to work correctly, you will need Pike
    7.0.268 or newer. For the sake of this example we assume that
    Caudium is installed in /opt/caudium/server/.
2.  Change directory to php-x.y.z (where x.y.z is the version number).
3.  ./configure --with-caudium=/opt/caudium/server
4.  make
5.  make install
6.  Restart Caudium if it's currently running.
7.  Log into the graphical configuration interface and go to the
    virtual server where you want to add PHP 4 support.
8.  Click Add Module and locate and then add the PHP 4 Script Support module.
9.  If the documentation says that the 'PHP 4 interpreter isn't
    available', make sure that you restarted the server. If you did
    check /opt/caudium/logs/debug/default.1 for any errors related to
    <filename>PHP4.so</filename>. Also make sure that 
    <filename>caudium/server/lib/[pike-version]/PHP4.so</filename>
    is present.
10. Configure the PHP Script Support module if needed.