Add a comment about fdGetMode, which doesn't work properly on Windows
fdGetMode :: Int -> IO IOMode
fdGetMode fd = do
#if defined(mingw32_TARGET_OS) || defined(__MINGW32__)
+ -- XXX: this code is *BROKEN*, _setmode only deals with O_TEXT/O_BINARY
flags1 <- throwErrnoIfMinus1Retry "fdGetMode"
(c__setmode (fromIntegral fd) (fromIntegral o_WRONLY))
flags <- throwErrnoIfMinus1Retry "fdGetMode"