diff --git a/pugs-compat.cabal b/pugs-compat.cabal
--- a/pugs-compat.cabal
+++ b/pugs-compat.cabal
@@ -1,5 +1,5 @@
 Name           : pugs-compat
-Version        : 0.0.5
+Version        : 0.0.6
 Build-type     : Simple
 Category       : Pugs
 License        : BSD3
@@ -16,13 +16,17 @@
 
   Build-depends   : base, haskell98, time, directory, process, regex-pcre-builtin, regex-base,
                     random, network, containers, bytestring, array, mtl, stm, utf8-string,
-                    stringtable-atom >= 0.0.4
+                    stringtable-atom >= 0.0.6
   Exposed-modules : Pugs.Compat
   Other-modules   : Pugs.Compat.Cast Pugs.Compat.Global Pugs.Compat.ID
                     Pugs.Compat.Monads Pugs.Compat.Posix Pugs.Compat.String
                     Pugs.Compat.Regex
 
-  Ghc-Options     : -fparr -Wall
+  if impl(ghc >= 6.10)
+      Ghc-Options   : -Wall
+
+  if impl(ghc < 6.10)
+      Ghc-Options   : -fparr -Wall
 
   Hs-source-dirs  : src
 
diff --git a/src/Pugs/Compat.hs b/src/Pugs/Compat.hs
--- a/src/Pugs/Compat.hs
+++ b/src/Pugs/Compat.hs
@@ -1,4 +1,5 @@
 {-# OPTIONS_GHC -fno-warn-unused-imports -fno-warn-orphans #-}
+{-# LANGUAGE PArr #-}
 {-|
     Internal utilities and library imports.
 
diff --git a/src/Pugs/Compat/Cast.hs b/src/Pugs/Compat/Cast.hs
--- a/src/Pugs/Compat/Cast.hs
+++ b/src/Pugs/Compat/Cast.hs
@@ -1,4 +1,5 @@
 {-# OPTIONS_GHC -fno-warn-unused-imports #-}
+{-# LANGUAGE PArr #-}
 module Pugs.Compat.Cast (
     (:>:)(..),
     (:<:)(..),