using fully qualified module names in Haskell source, which seems to be required by GHC 7.0.4

--- a/src/HOL/Tools/Quickcheck/Narrowing_Engine.hs	Thu Jan 26 09:52:47 2012 +0100
+++ b/src/HOL/Tools/Quickcheck/Narrowing_Engine.hs	Thu Jan 26 10:59:47 2012 +0100
@@ -1,6 +1,6 @@
 module Narrowing_Engine where {
 
-import Monad;
+import Control.Monad;
 import Control.Exception;
 import System.IO;
 import System.Exit;

--- a/src/HOL/Tools/Quickcheck/narrowing_generators.ML	Thu Jan 26 09:52:47 2012 +0100
+++ b/src/HOL/Tools/Quickcheck/narrowing_generators.ML	Thu Jan 26 10:59:47 2012 +0100
@@ -239,7 +239,8 @@
         val narrowing_engine_file = Path.append in_path (Path.basic "Narrowing_Engine.hs")
         val main_file = Path.append in_path (Path.basic "Main.hs")
         val main = "module Main where {\n\n" ^
-          "import System;\n" ^
+          "import System.IO;\n" ^
+          "import System.Environment;\n" ^
           "import Narrowing_Engine;\n" ^
           "import Generated_Code;\n\n" ^
           "main = getArgs >>= \\[potential, size] -> " ^