Remove warning flags from individual compiler modules

We now set the flags once and for all in compiler/Makefile.

compiler/cmm/CmmCPSZ.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
 
 module CmmCPSZ (
   -- | Converts C-- with full proceedures and parameters

compiler/cmm/CmmContFlowOpt.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+
 module CmmContFlowOpt
     ( runCmmOpts, cmmCfgOpts, cmmCfgOptsZ
     , branchChainElimZ, removeUnreachableBlocksZ

compiler/cmm/CmmCvt.hs

 {-# LANGUAGE PatternGuards #-}
-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
 
 module CmmCvt
   ( cmmToZgraph, cmmOfZgraph )

compiler/cmm/CmmExpr.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
 
 module CmmExpr
     ( CmmExpr(..), cmmExprRep, maybeInvertCmmExpr

compiler/cmm/CmmLiveZ.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+
 module CmmLiveZ
     ( CmmLive
     , cmmLivenessZ

compiler/cmm/CmmProcPointZ.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+
 module CmmProcPointZ
     ( minimalProcPointSet
     , addProcPointProtocols

compiler/cmm/CmmSpillReload.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
 
 module CmmSpillReload
   ( ExtendWithSpills(..)

compiler/cmm/CmmTx.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+
 module CmmTx where
 
 data ChangeFlag = NoChange | SomeChange

compiler/cmm/CmmZipUtil.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
-module CmmZipUtil 
+
+module CmmZipUtil
   ( zipPreds
   )
 where
 import Prelude hiding (last, unzip)
-import ZipCfg 
+import ZipCfg
 import Maybes
 
 -- | Compute the predecessors of each *reachable* block

compiler/cmm/DFMonad.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+
 module DFMonad
     ( OptimizationFuel
     , DFTx, runDFTx, lastTxPass, txDecrement, txRemaining, txExhausted

compiler/cmm/MkZipCfg.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 module MkZipCfg
     ( AGraph, (<*>), emptyAGraph, withFreshLabel, withUnique
     , mkMiddle, mkMiddles, mkLast, mkZTail, mkBranch, mkLabel, mkIfThenElse, mkWhileDo

compiler/cmm/StackColor.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+
 module StackColor where
 
 import StackPlacements

compiler/cmm/StackPlacements.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+
 module StackPlacements
   ( SlotSet, allStackSlots  -- the infinite set of stack slots
   , SlotClass(..), slotClassBits, stackSlot32, stackSlot64, stackSlot128

compiler/cmm/ZipCfg.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 module ZipCfg
     ( BlockId(..), freshBlockId
     , BlockEnv, emptyBlockEnv, lookupBlockEnv, extendBlockEnv, insertBlock, mkBlockEnv

compiler/cmm/ZipCfgCmmRep.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+
 
 -- This module is pure representation and should be imported only by
 -- clients that need to manipulate representation and know what

compiler/cmm/ZipDataflow.hs

-{-# OPTIONS -Wall -fno-warn-name-shadowing #-}
+
 {-# LANGUAGE MultiParamTypeClasses #-}
 module ZipDataflow
   ( Answer(..)