dxvk: move Darwin detection to the wrapper package

pkgs/misc/dxvk/default.nix

@@ -8,8 +8,12 @@
 
 stdenvNoCC.mkDerivation (finalAttrs:
   let
-    dxvk32 = if stdenv.isDarwin then pkgsCross.mingw32.dxvk_1 else pkgsCross.mingw32.dxvk_2;
-    dxvk64 = if stdenv.isDarwin then pkgsCross.mingwW64.dxvk_1 else pkgsCross.mingwW64.dxvk_2;
+    dxvk32 = if stdenv.isDarwin
+      then pkgsCross.mingw32.dxvk_1.override { enableMoltenVKCompat = true; }
+      else pkgsCross.mingw32.dxvk_2;
+    dxvk64 = if stdenv.isDarwin
+      then pkgsCross.mingwW64.dxvk_1.override { enableMoltenVKCompat = true; }
+      else pkgsCross.mingwW64.dxvk_2;
   in
   {
     pname = "dxvk";

pkgs/misc/dxvk/dxvk.nix

@@ -14,6 +14,7 @@
 , gitUpdater
 , sdl2Support ? true
 , glfwSupport ? false
+, enableMoltenVKCompat ? false
 }:
 
 # SDL2 and GLFW support are mutually exclusive.
@@ -35,7 +36,7 @@ let
         hash = "sha256-T93ZylxzJGprrP+j6axZwl2d3hJowMCUOKNjIyNzkmE=";
       };
       # These patches are required when using DXVK with Wine on Darwin.
-      patches = lib.optionals stdenv.buildPlatform.isDarwin [
+      patches = lib.optionals enableMoltenVKCompat [
         # Patch DXVK to work with MoltenVK even though it doesn’t support some required features.
         # Some games work poorly (particularly Unreal Engine 4 games), but others work pretty well.
         ./darwin-dxvk-compat.patch