How can a value be added to $_SERVER?

Question

PHP

Good afternoon!
The site code uses $_SERVER['PHPROOT'] - the path to the folder with the site, but I don't have such a key at all and it turns out that the whole code does not work.
the problem is that I can't just set $_SERVER['PHPROOT'] = 'path to the folder on my computer'; since this part of the code cannot be touched :) can you specify something in the server settings? php 5.3 apache 2.2

Answer 1

install xampp

Answer 2

.htaccess
php_value PHPROOT "/home/site"