haskell-generic-builder: re-enable support for running jailbreak-cabal
hackage-packages.nix: manually jailbreak ChasingBottoms
haskell-generic-builder: add 'hasActiveLibrary' convenience variable
haskell-generic-builder: run haddock only if the package contains a library
haskell-generic-builder: prepend "haskell-" to Haskell library names