darcs patch: a faster appendFS

[Christoph Bauer]

>> Sat Feb 27 22:16:59 CET 2010  ich at christoph-bauer.net
>>    * a faster appendFS
>
> Thanks - looks ok, I'll test and apply. What prompted you to improve
> appendFS?

I started to read a bit in the internals of ghc (to improve my haskell).
There was a Todo-comment next to appendFS+concatFS. Because concatFS is
nowhere used in the code, so I thought appendFS is good and simple
candidate to check, how the patch machinery of ghc works...

Christoph Bauer