patch applied (packages/Cabal): Add read/show for CompilerFlavour like for OS and Arch

[Ian Lynagh]

Tue Mar  4 17:08:20 PST 2008  Duncan Coutts <duncan at haskell.org>
  * Add read/show for CompilerFlavour like for OS and Arch
  Also add YHC compiler flavour.

    M ./Distribution/Compiler.hs -10 +37

View patch online:
http://darcs.haskell.org/packages/Cabal/_darcs/patches/20080305010820-adfee-38920f6fec06fec51e62c5fb2dde629756b43b8c.gz