rm-old-base: restore builds not of cabal itself

The #ifdefs being generated need to be kept here so that projects other
than cabal can be built using older ghc versions and current cabal
versions.

Cabal/src/Distribution/Simple/Build/PathsModule/Z.hs

@@ -85,7 +85,11 @@ render z_root = execWriter $ do
   then do
     tell "#if defined(VERSION_base)\n"
     tell "\n"
+    tell "#if MIN_VERSION_base(4,0,0)\n"
     tell "catchIO :: IO a -> (Exception.IOException -> IO a) -> IO a\n"
+    tell "#else\n"
+    tell "catchIO :: IO a -> (Exception.Exception -> IO a) -> IO a\n"
+    tell "#endif\n"
     tell "\n"
     tell "#else\n"
     tell "catchIO :: IO a -> (Exception.IOException -> IO a) -> IO a\n"