cdrtools: mark as broken

https://github.com/NixOS/nixos/issues/231
haskell-cabal2nix: update to version 1.64
haskellPackages: use static-enabled 'gmp' to enable statically linked Haskell binaries

Pass '-optl-static -optl-pthread' to GHC to enable static linking.

Fixes <https://github.com/NixOS/nixpkgs/issues/3193>. Further details can be
found at <http://permalink.gmane.org/gmane.linux.distributions.nixos/13526>.
ghc: update version 7.8.2 to 7.8.3
haskell-packages.nix: cosmetic
Switch default Haskell compiler to GHC 7.8.3.
cabal: cosmetic
cryptol2: build with ghc 7.6.3 to avoid errors with 7.8.x
darcs: build with ghc 7.6.3 to avoid errors with 7.8.x