fix for invalid preprocessing directive on OS X Maverick

On OS X Maverick the compiler misunderstands 
#-}
at the end of a line as a malformed preprocessing directive. Putting it at the end of the previous line fixes that - or at least it builds.

    dist/dist-sandbox-4c20042d/build/Crypto/Skein/Internal.hs:6:3:
         error: invalid preprocessing directive
         #-}
          ^

(fix for bug perceived on OS X Maverick, probably due to local command-line build tools,
Glasgow Haskell Compiler, Version 7.6.3, stage 2 booted by GHC version 7.4.2)