This is custom PKGBUILD for Nginx which adds Phusion Passenger support.
In order to build this package you need to have passenger gem installed on your system:
gem install passenger
Now make sure passenger-config script is available in your path:
passenger-config --root
This should print path to passenger installation directory. Use it later as a path given to passenger_root option in Nginx's config.
Now you can build the package:
cd nginx-passenger
makepkg
sudo pacman -Su nginx-passenger-....pkg.tar.xz