they must be compiled when you build the PHP install package for linux.
you will need to refer to the php.net instruction for installing php in linux there should be a section there on compiling additional libraries.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.