If you don’t want to build anything that could ever potentially be used in the manufacture of those weapons, you probably shouldn’t be building open source software or contributing anything to do with any programming language at all.
Open Source means you can't really prohibit Anduril from using your projects; but _welcoming_ them and their money is a different matter altogether.
I did, however, have to expand on the concept that it's very easy to have strong opinions about war when you yourself are sheltered from the consequences of it.