I mean, my remark was a bit of an oversimplification. Modern build systems do a bit more than take a list of dependencies--they'll also allow for bundling data

I mean, my remark was a bit of an oversimplification. Modern build systems do a bit more than take a list of dependencies--they'll also allow for bundling data files into the compiled artifact, platform-conditional compilation units, and a few other things. But they don't expose these things as a fully imperative scripting language / meta build system--a few bits of declarative configuration can cover 99.9% of use cases.