My system has two PHP interpreters. One came bundled with the OS and the other I installed via the XAMPP package. All of my PHP extensions are applied to the XAMPP installat
In agreement with Thomas' statement, additionally there's a line further below
if (strpos('/Applications/MAMP/bin/php5.3/bin/php', '@php_bin') === 0) {
set_include_path(dirname(__FILE__) . PATH_SEPARATOR . get_include_path());
}
That I've been told you're also supposed to change to reflect the PHP you're interested in using (I've set mine to MAMP obviously)
I've switched back and forth from 5.2 and 5.3 a lot recently :)