haskell-ghc-paths: register Nixpkgs-specific patch

This used to be added by cabal2nix, but now the tool no longer does because
there's no reliable way to refer to the patch file in the generated build
expression.

pkgs/development/haskell-modules/configuration-common.nix

@@ -14,6 +14,9 @@ self: super: {
   # Link statically to avoid runtime dependency on GHC.
   jailbreak-cabal = disableSharedExecutables super.jailbreak-cabal;
 
+  # Apply NixOS-specific patches.
+  ghc-paths = appendPatch super.ghc-paths ./patches/ghc-paths-nix.patch;
+
   # Break infinite recursions.
   Dust-crypto = dontCheck super.Dust-crypto;
   hasql-postgres = dontCheck super.hasql-postgres;