haskell-snap-core: jailbreak to fix build with recent versions of 'text'

pkgs/development/libraries/haskell/snap/core.nix

@@ -17,6 +17,7 @@ cabal.mkDerivation (self: {
     HUnit MonadCatchIOTransformers mtl random regexPosix text time
     unixCompat unorderedContainers vector zlibEnum
   ];
+  jailbreak = true;
   meta = {
     homepage = "http://snapframework.com/";
     description = "Snap: A Haskell Web Framework (core interfaces and types)";