- detection/management of external dependencies - defining different build types (debug/release) - optionally building and running tests - incremental builds

- detection/management of external dependencies - defining different build types (debug/release) - optionally building and running tests - incremental builds (detecting what has changed) That doesn't necessarily run counter to the concept of a DAG, but the organizational structures to manage this is what makes the build system. Topologically sorting the dependencies isn't the hard part. That's why make isn't a build system. It is the generic DAG runner, but that's not sufficient.