# cd /usr/local/src/php-5.2.17/ext/simplexml
# /usr/local/php-5.2.17/bin/phpize
# ./configure --with-php-config=/usr/local/php-5.2.17/bin/php-config
# make
# make test
# make install
# cp /usr/local/php-5.2.17/lib/php/extensions/no-debug-zts-20060613/simplexml.so /usr/local/php-5.2.17/lib/php/extensions/
extension_dir = "/usr/local/php-5.2.17/lib/php/extensions/"
extension=simplexml.so