Add System.Timeout to base.cabal

Filtered out for non-GHC by Setup.hs.

Setup.hs

@@ -120,7 +120,7 @@ isPortableBuild :: String -> Bool
 isPortableBuild s
  | "GHC" `isPrefixOf` s = False
  | "Data.Generics" `isPrefixOf` s = False
- | otherwise = s `notElem` ["Foreign.Concurrent"]
+ | otherwise = s `notElem` ["Foreign.Concurrent", "System.Timeout"]
 
 forGHCBuild :: String -> Bool
 forGHCBuild = ("GHC.Prim" /=)

base.cabal

@@ -149,6 +149,7 @@ exposed-modules:
 	System.Posix.Internals,
 	System.Posix.Signals,
 	System.Posix.Types,
+	System.Timeout,
 	Text.ParserCombinators.ReadP,
 	Text.ParserCombinators.ReadPrec,
 	Text.Printf,