[Haskell-beginners] How to include {-# LANGUAGE LambdaCase #-} at the ghci prompt

I've got this code I've entered into the ghci by hand between :{ and :} :{ {-# LANGUAGE LambdaCase #-} data List a = Empty | Cons a (List a) deriving (Eq, Ord, Show) infixr 5 `Cons` subst_c :: (a -> Bool) -> (a, MyList a) -> MyList a subst_c pred = \ case (_, Empty) -> Empty (n, Cons e t) | pred e -> Cons n $ subst_c pred (n, t) | otherwise -> Cons e $ subst_c pred (n, t) :} but I keep getting the error Illegal lambda-case (use -XLambdaCase) This works fine inside an .hs file and :load and run at the prompt. However, I'm using Emacs org-mode and need to keep everything limited to a version of hand-entered :{ ... :}. Any suggestions? LB