Their lists of dependencies fully depend on the code, of course, it doesn't need to be magically agnostic of everything. But using something not available for a

Their lists of dependencies fully depend on the code, of course, it doesn't need to be magically agnostic of everything. But using something not available for a specific target should be a compilation error. And there needs to be a build system that wraps the compiled outputs into deployables. It's not the compiler's job to know how to deploy the code, it only needs to know the target architectures that can be deployed. (I'm not sure I fully understand the question.)