[aur-general] How to depend a pkg on two alternative packages?

Hello, I want to create a package for an app that needs either pyaudio or (as an alternative) pygame. How can I write this in the PKGBUILD? And what's more: The main dependency pyaudio is "only" in AUR but the alternative "pygame" is part of the official repos. For now, I don't know when the app decides what package to use. So I see three ways to do it: * make both packages alternatives in the depends-array (but how?) * make pygame a hard dependency (because it is an official package) and pyaudio an optional one * make both optional and write a message to .install, that at least one of them has to be installed ... Could you help me? Uwe