Use explicit language extensions & remove extension fields from base.cabal

Add explicit {-# LANGUAGE xxx #-} pragmas to each module, that say
what extensions that module uses.  This makes it clearer where
different extensions are used in the (large, variagated) base package.

Now base.cabal doesn't need any extensions field

Thanks to Bas van Dijk for doing all the work.

4 files changed, 20 insertions, 5 deletions

diff --git a/libraries/base/GHC/Conc/IO.hs b/libraries/base/GHC/Conc/IO.hs
index ca75894dbc..fc800261b0 100644
--- a/libraries/base/GHC/Conc/IO.hs
+++ b/libraries/base/GHC/Conc/IO.hs
@@ -1,6 +1,12 @@
-{-# OPTIONS_GHC -XNoImplicitPrelude #-}
+{-# LANGUAGE CPP
+           , NoImplicitPrelude
+           , MagicHash
+           , UnboxedTuples
+           , ForeignFunctionInterface
+  #-}
 {-# OPTIONS_GHC -fno-warn-missing-signatures #-}
 {-# OPTIONS_HADDOCK not-home #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  GHC.Conc.IO
diff --git a/libraries/base/GHC/Conc/Signal.hs b/libraries/base/GHC/Conc/Signal.hs
index 6d300c6380..851c4bb72c 100644
--- a/libraries/base/GHC/Conc/Signal.hs
+++ b/libraries/base/GHC/Conc/Signal.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE NoImplicitPrelude, ForeignFunctionInterface #-}
 
 module GHC.Conc.Signal
         ( Signal
diff --git a/libraries/base/GHC/Conc/Sync.lhs b/libraries/base/GHC/Conc/Sync.lhs
index 0808e68f21..b4de53a636 100644
--- a/libraries/base/GHC/Conc/Sync.lhs
+++ b/libraries/base/GHC/Conc/Sync.lhs
@@ -1,8 +1,16 @@
 \begin{code}
-{-# LANGUAGE BangPatterns #-}
-{-# OPTIONS_GHC -XNoImplicitPrelude #-}
+{-# LANGUAGE CPP
+           , NoImplicitPrelude
+           , BangPatterns
+           , MagicHash
+           , UnboxedTuples
+           , UnliftedFFITypes
+           , ForeignFunctionInterface
+           , DeriveDataTypeable
+  #-}
 {-# OPTIONS_GHC -fno-warn-missing-signatures #-}
 {-# OPTIONS_HADDOCK not-home #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  GHC.Conc.Sync
diff --git a/libraries/base/GHC/Conc/Windows.hs b/libraries/base/GHC/Conc/Windows.hs
index b750185586..96f034cfb8 100644
--- a/libraries/base/GHC/Conc/Windows.hs
+++ b/libraries/base/GHC/Conc/Windows.hs
@@ -1,6 +1,7 @@
-{-# OPTIONS_GHC -XNoImplicitPrelude #-}
+{-# LANGUAGE NoImplicitPrelude #-}
 {-# OPTIONS_GHC -fno-warn-missing-signatures #-}
 {-# OPTIONS_HADDOCK not-home #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  GHC.Conc.Windows