--recursive updates are not useful

[avdgrinten]

--recursive currently checks for updates along edges of the dependency graph. It also tries to redo all steps that can reach these updates. However, this strategy is overly broad: for example, it tends to rebuild toolchains that depend on some package that was changed (e.g., a libc).

It would be more useful if --recursive only redid steps that reach the updates by build edges (but the check for updates should still follow all edges).