5.2.1をインストール

$ ./configure  --prefix=/usr/local/php-5.2.1 \
 --with-pdo=shared --with-zlib \
 --with-xsl=/usr/lib --with-libxml-dir=/usr/lib \
 --with-apxs2=/usr/local/apache2.2/bin/apxs \
 --with-mysql=shared,/usr/local/mysql5 --with-pdo-mysql=shared,/usr/local/mysql5 \
 --enable-calendar --enable-gd-native-ttf \
 --enable-ftp --enable-cli --enable-sockets \
 --enable-trans-sid --enable-track-vars \
 --enable-mbstring --enable-mbregex --enable-zend-multibyte

info.phpを作って、設定を確認。

<?php phpinfo(); ?>