In most cases, usage does not return, so mark them as __dead2. For the
cases where they do return, they have not been marked __dead2.
Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/735
This program is trash and there's no reason to keep it in base. But as long as
we're shipping a silly program named 'random', let's actually make it random.
