What do I need to develop a PHP extension in lampp?

Question

Actually I'm dealing with a trouble in my system, I have to delivery the system to clients and it was built in PHP, JS, ShellScript and SQL.

I would like to encrypt the code or obfuscate it from eyes of others! Then someone from the community told me about building my own PHP extension, it sounds to me as a great idea, since it will not be with the main code of the system.

But I have a problem doing this way, if a programmer get in the extensions and find it, all the hard work has gone. Then I'm here to ask again about this matter.

What is the best way to hide my Business Logic from third parties?

I know that there are stuff like IonCube, Zend Guard, and many others. But I'm looking something that I can build myself.

Is PHP extension the right way to follow? Or some Half SaaS system, with dependencies (Business Logic) in a remote server?

About the environment

OS: Kernel Linux 2.6.37.1-1.2 - LAMPP (Apache 2.2, MySQL 5.5 PHP 5.3.8)

In php generally the extension is located at /php/ext/ but in lampp I have no idea where it is, I just found a folder /opt/lampp/lib/php/extensions/ is that right place?