patch applied (packages/base): import Control.Arrow.ArrowZero to help nhc98' s type checker

[Ross Paterson]

On Thu, Aug 31, 2006 at 03:14:50AM -0700, Malcolm Wallace wrote:
> Thu Aug 31 03:11:05 PDT 2006  Malcolm.Wallace at cs.york.ac.uk
>   * import Control.Arrow.ArrowZero to help nhc98's type checker
> 
>     M ./Data/Foldable.hs +1

That's an unusual, um, feature.  The module doesn't use arrows at all,
but it uses a class, one of whose instances (defined elsewhere) uses
ArrowZero.  Does this happen a lot?