Installing Drupal 7 locally

When I run the insta开发者_JS百科ll I get the same error:

Your PHP installation is too old. Drupal requires at least PHP 5.2.5, or PHP 5.2.4 with the htmlspecialchars security patch backported.

After a few hours of research it seems incredibly complicated to upgrade my version of php (currently 5.2.4 locally on my mac os x 10.4.11) so it appears I need to 'backport the htmlspecialchars security patch'.

Can anyone please point me in the right direction for how to do this? I can't seem to find any documentation.

Have you tried one of the PHP packages from http://www.entropy.ch/software/macosx/php/ to upgrade your local PHP installation?