Proposal: add clearEnv and setEnvironment to System.Posix.Env

Hi all, System.Posix.Env doesn't currently define a binding for the POSIX function clearenv. I propose to add: clearEnv :: IO () setEnvironment :: [(String, String)] -> IO () 'clearEnv' is a direct wrapper for the underlying function, while 'setEnvironment' is a higher-level utility function which mirrors the interface of the existing 'getEnvironment'. See attached patches here: http://hackage.haskell.org/trac/ghc/ticket/5648. Discussion deadline: 24 Mar 2012. BR, Paolo