After compile install php 5.3.1, I can not find my php.ini file

From the INSTALL file in php-5.3.1.tar.gz:

13. Setup your php.ini file:

PHP will use the built-in default values if no php.ini file was
placed in the configuration directory. The default location is
/usr/local/lib, if you prefer your php.ini in another location, use 
--with-config-file-path=/some/path in step 10.

The PHP distribution provides two sample php.ini files, you can use them
by
  cp php.ini-development /usr/local/lib/php.ini
or
  cp php.ini-production  /usr/local/lib/php.ini

If you choose one of these php.ini files be certain to read the list
of changes within, as they affect how PHP behaves.

You need to create the php.ini file. This can be done by copying one of the sample files.