darwin.developer_cmds: wrap clang -E from clang-wrapped as clang-cpp

pkgs/os-specific/darwin/apple-source-releases/developer_cmds/default.nix

@@ -1,7 +1,7 @@
-{ lib, appleDerivation, xcbuildHook, llvmPackages }:
+{ lib, appleDerivation, xcbuildHook, llvmPackages, makeWrapper }:
 
 appleDerivation {
-  nativeBuildInputs = [ xcbuildHook ];
+  nativeBuildInputs = [ xcbuildHook makeWrapper ];
 
   patches = [
     # The following copied from
@@ -11,8 +11,9 @@ appleDerivation {
   ];
 
   postPatch = ''
+    makeWrapper ${llvmPackages.clang}/bin/clang $out/bin/clang-cpp --add-flags "--driver-mode=cpp"
     substituteInPlace rpcgen/rpc_main.c \
-      --replace "/usr/bin/cpp" "${llvmPackages.clang-unwrapped}/bin/clang-cpp"
+      --replace "/usr/bin/cpp" "$out/bin/clang-cpp"
   '';
 
   # temporary install phase until xcodebuild has "install" support