Установка и настройка
PHP Manual


xdiff is currently available through PECL » http://pecl.php.net/package/xdiff.

If » PEAR is available on your *nix-like system you can use the pear installer to install the xdiff extension, by the following command: pear -v install xdiff.

You can always download the tar.gz package and install xdiff by hand:

Пример #1 xdiff install by hand

gunzip xdiff-xxx.tgz
tar -xvf xdiff-xxx.tar
cd xdiff-xxx
./configure && make && make install

Установка и настройка
PHP Manual