Problem with handles in GHC from CVS

Cabal uses something like system "ghc --version >tmp" in order to determine the version of GHC. After the last changes in CVS the above line no longer produces the right result. The temporary file is created but it is empty. It seems like the stdout/stderr handles are flushed in GHC.TopHandler.runMainIO but only if the program terminates without exception. I tried to flush handles in the catch clause but this doesn't help. Any ideas? Cheers, Krasimir