Configure Apache to interpret PHP scripts

Params:
- Linux solar 3.1.6-gentoo #16 SMP Thu Jan 5 14:49:10 GMT 2012 x86_64 AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ AuthenticAMD GNU/Linux,
- PHP 5.3.8-pl0-gentoo,
- Apache/2.2.21 (Unix)

Problem:
Apache not interpret php scripts, theirs content printed in browser.

Solution:
Edit apache config file /etc/conf.d/apache2 (don't forget this is gentoo!)
Find string where defined parameter APACHE2_OPTS and add "-D PHP5" to his value.