Drop use of CPP in `bin-package-db`

This also removes the redundant `default-extensions` field in
`bin-package-db.cabal` and adds an `other-extensions` field instead.
Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>

libraries/bin-package-db/Distribution/InstalledPackageInfo/Binary.hs

-{-# LANGUAGE CPP, RecordWildCards, TypeSynonymInstances, StandaloneDeriving, GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE RecordWildCards, Trustworthy, TypeSynonymInstances, StandaloneDeriving,
+             GeneralizedNewtypeDeriving #-}
 {-# OPTIONS_GHC -fno-warn-name-shadowing #-}
 -- This module deliberately defines orphan instances for now. Should
 -- become unnecessary once we move to using the binary package properly:
 {-# OPTIONS_GHC -fno-warn-orphans #-}
-#if __GLASGOW_HASKELL__ >= 701
-{-# LANGUAGE Trustworthy #-}
-#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Distribution.InstalledPackageInfo.Binary

libraries/bin-package-db/bin-package-db.cabal

@@ -14,6 +14,12 @@ source-repository head
 
 Library
     default-language: Haskell2010
+    other-extensions:
+            GeneralizedNewtypeDeriving
+            RecordWildCards
+            StandaloneDeriving
+            Trustworthy
+            TypeSynonymInstances
 
     exposed-modules:
             Distribution.InstalledPackageInfo.Binary
@@ -22,4 +28,3 @@ Library
                    binary >= 0.5 && < 0.8,
                    Cabal >= 1.20 && < 1.21
 
-    default-extensions: CPP