bug in System.system on ghc-6.2.1

[Malcolm Wallace]

Using the glibc-2.2 (RedHat 7) Linux binary package of ghc-6.2.1,
the following program:

    import System.Cmd
    main = do v <- system("ghc --version 2>&1")
              print v

incorrectly gives

    ExitFailure 127

whereas with the glibc-2.3 Linux binary package of ghc-6.2.1, the
same program correctly gives

    The Glorious Glasgow Haskell Compilation System, version 6.2.1
    ExitSuccess

If we change the use of "system" to "rawSystem", both versions work fine.

    import System.Cmd
    main = do v <- rawSystem "ghc" ["--version","2>&1"]
              print v

However, rawSystem is not portable across compiler implementations,
whereas System.system is supposed to be.

Regards,
    Malcolm