Is zlib included or not?

[LeFou]

Am trying to install 1.6.1, the devel stuff, PDO and Zend Framework. xampp page indicates that zlib is included, but
pear install http://pecl.php.net/get/PDO-1.0.3.tgz

gives me
The extension 'zlib' couldn't be found.

Sure enough, the only zlib-related line in php.ini is the windows one:

;extension=php_zlib.dll

Any pointers?

[Wiedmann]

Is zlib included or not?

What does phpinfo() tell you?