Changes to ghc

Changes to ghc:
commit 5e4bdb5fc5e741522cbb787731422da3f12aa398
Author: Iavor S. Diatchki <diatchki@galois.com>
Date:   Tue Mar 18 18:54:23 2014 -0700

    Implement ordering comparisons for type-level naturals and symbols.

    This is done with two built-in type families: `CmpNat and `CmpSymbol`.
    Both of these return a promoted `Ordering` type (EQ, LT, or GT).