patch applied (packages/base): improve performance of Integer-> String conversion

[Simon Marlow]

Wed May  3 04:33:06 PDT 2006  Simon Marlow <simonmar at microsoft.com>
  * improve performance of Integer->String conversion
  See
   http://www.haskell.org//pipermail/libraries/2006-April/005227.html
  
  Submitted by: bertram.felgenhauer at googlemail.com
  
  

    M ./GHC/Num.lhs -6 +76