Review swaps

A new version of cvc4 is available. It depends on cryptominisat 5.x
instead of 4.x. Since cvc4 was the last consumer of cryptominisat 4.x
in Fedora, this means that we can finally retire the cryptominisat4

On the other hand, cvc4 1.6 has new dependencies. I get to add 4
packages in order to retire 1. Um ... yay?

I need reviews for the following. Let me know what I can review for
you in exchange:
- drabt: <a href="" title=""></a>
- cadical: <a href="" title=""></a>, depends on drabt
- lfsc: <a href=";" title=";">;</a> see note below
- symfpu: <a href="" title=""></a>

We used to have an lfsc package in Fedora. Then cvc4 absorbed lfsc;
the upstream lfsc repository disappeared, and the sources were shipped
as part of cvc4. Now the cvc4 developers have decided to distribute
lfsc separately again, so we need to revive the old lfsc package (with
some substantial changes).

Thank you,