Use \{ \} in regex instead of { } for literal { }.
Hope it should be OK in theory; needed in practice here.
{-# OPTIONS -W #-}
-----------------------------------------------------------------------------
--- $Id: Main.hs,v 1.51 2000/08/06 12:19:21 panne Exp $
+-- $Id: Main.hs,v 1.52 2000/08/07 23:29:46 qrczak Exp $
--
-- GHC Driver program
--
-> return (words opts)
| otherwise -> return []
-optionRegex = mkRegex "{-#[ \t]+OPTIONS[ \t]+(.*)#-}"
+optionRegex = mkRegex "\\{-#[ \t]+OPTIONS[ \t]+(.*)#-\\}"
-----------------------------------------------------------------------------
-- Main loop