When setuptools is broken, emerging dev-python/markupsafe fails with an ImportError, "no module named setuptools." Re-emerging setuptools fixes the problem with markupsafe. We need a dependency on setuptools in markupsafe so that revdep-rebuild gets the sequence right.
Apologies; markupsafe already has this dependency. For some reason revdep-rebuild didn't notice that setuptools is broken, so it didn't include it in its computation. I am closing this bug.