Backport #10723: Remove unused -XCPP (#10752)

* Remove redundant -XCPP

- Remove redundant -XCPP from Cabal-tree-diff
- Remove redundant -XCPP from cabal-install
- Remove redundant -XCPP from Cabal
- Remove redundant -XCPP from Cabal-QuickCheck
- Remove redundant -XCPP from Cabal-syntax
- Remove redundant -XCPP from Cabal-tests
- Remove redundant -XCPP from cabal-testsuite

(cherry picked from commit 7965c7f)

# Conflicts:
#	Cabal-syntax/src/Distribution/Compat/Binary.hs
#	Cabal-syntax/src/Distribution/Utils/Generic.hs
#	cabal-install/src/Distribution/Client/CmdUpdate.hs
#	cabal-install/src/Distribution/Client/InstallSymlink.hs
#	cabal-install/src/Distribution/Client/Targets.hs

* fix conflicts

---------

Co-authored-by: Phil de Joux <[email protected]>
Co-authored-by: Hécate <[email protected]>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: 3 people

Cabal-QuickCheck/src/Test/QuickCheck/GenericArbitrary.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP              #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE GADTs            #-}
 {-# LANGUAGE TypeOperators #-}

Cabal-syntax/src/Distribution/Compat/Binary.hs

@@ -1,6 +1,3 @@
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE PatternSynonyms #-}
-
 module Distribution.Compat.Binary
   ( decodeOrFailIO
   , decodeFileOrFail'

Cabal-syntax/src/Distribution/Compat/Exception.hs

@@ -1,5 +1,3 @@
-{-# LANGUAGE CPP #-}
-
 module Distribution.Compat.Exception
   ( catchIO
   , catchExit

Cabal-syntax/src/Distribution/Compat/Graph.hs

@@ -1,15 +1,10 @@
 {-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-}
 
------------------------------------------------------------------------------
-
------------------------------------------------------------------------------
-
 -- |
 -- Module      :  Distribution.Compat.Graph
 -- Copyright   :  (c) Edward Z. Yang 2016

Cabal-syntax/src/Distribution/Compat/MonadFail.hs

@@ -1,5 +1,3 @@
-{-# LANGUAGE CPP #-}
-
 -- | Compatibility layer for "Control.Monad.Fail"
 module Distribution.Compat.MonadFail (Control.Monad.Fail.MonadFail (fail)) where
 

Cabal-syntax/src/Distribution/Compat/Newtype.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DefaultSignatures #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE FunctionalDependencies #-}

Cabal-syntax/src/Distribution/Compat/Prelude.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE Trustworthy #-}

Cabal-syntax/src/Distribution/Compat/Semigroup.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}

Cabal-syntax/src/Distribution/FieldGrammar/Class.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE ConstraintKinds #-}
 {-# LANGUAGE FunctionalDependencies #-}
 {-# LANGUAGE RankNTypes #-}

Cabal-syntax/src/Distribution/Fields/ParseResult.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE RankNTypes #-}