At the LAMP and Beyond III event (run by PHPNW) this weekend we set ourselves the task of giving PHP7 a go. Below is some nodes from that session.
This assumes that you’ve already installed PHP5.6 along with Apache and MySQL. Installing PHP5.6 via apt-get is fine as we just need some of the dependencies to be present.
To get the the code for PHP7 you need to clone from the PHP repo on Github.