Changes to ghc

Changes to ghc:
commit bcd989d13072a189b49d9393b0d4b1bbaede9d36
Author: Herbert Valerio Riedel <hvr@gnu.org>
Date:   Mon Apr 21 20:29:15 2014 +0200

    Generalise type of recently added System.Exit.die

    This is a follow-up to 77ea2eb0ab36d1a (re #9016) which added `die` with a
    return type of `IO ()` even though all other functions in System.Exit have
    the more general return type `IO a`. It is assumed this was an oversight in
    the original proposal.

    Acked-by: Edward Kmett <ekmett@gmail.com>
    Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>