Default dir for PHP source files?

[roger at audiblefaith.com]

Ok, I can not seem to find the directory for the PHP source files. No *PHP* or *php* directories contain the files. I need to reconfigure PHP and can't find the place to do so.

I installed PHP with RPM:
php-4.2.2-17.2.i386.rpm

Does anyone know where these files are supposed to be?

Thanks in advance for answering my silly question,
Roger