Disable Hydra builds for all "old" Haskell packages.

Old means that we have a newer version in Nixpkgs already. If there is a reason
for the old package to still exist, i.e. because some other package is still
referring to it, then Hydra will still build the package as a dependency, but
we won't want to build old packages on their own right.

pkgs/development/libraries/haskell/preprocessor-tools/0.1.3.nix

@@ -12,5 +12,6 @@ cabal.mkDerivation (self: {
     description = "A framework for extending Haskell's syntax via quick-and-dirty preprocessors";
     license = self.stdenv.lib.licenses.bsd3;
     platforms = self.ghc.meta.platforms;
+    hydraPlatforms = self.stdenv.lib.platforms.none;
   };
 })