The build process requires several parts. To ease everything,
you can use Phing and run the provided build.xml file.
Phing can also be installed by adding phing/phing to the
composer.json. You also need install Box, e.g. via
homebrew.
Simply install Phing on your local computer and run it in the
root directory. The result will be a contao-manager.phar file
in the root.
If you want to test your changes and want to create a phar from
the files you have currently checked out, run
[vendor/bin/]phing debug.