patch applied (packages/Cabal): Add checks for unknown OS Arch and Compiler names

[Ian Lynagh]

Wed Apr 23 08:14:10 PDT 2008  Duncan Coutts <duncan at haskell.org>
  * Add checks for unknown OS Arch and Compiler names
  They're ok locally but for distribution they need to be known.

    M ./Distribution/PackageDescription/Check.hs -4 +47

View patch online:
http://darcs.haskell.org/packages/Cabal/_darcs/patches/20080423151410-adfee-d013d0384679463f7e28471cc18ee6b40f6dc6d9.gz