simplify pkgsCuda exclusion

hardware/gpu/cuda-common.nix

@@ -36,30 +36,46 @@ lib.mkMerge [
     ];
 
   # avoid expensive rebuilds
-  nixpkgs.config.packageOverrides = pkgs: {
-    firefox-unwrapped = pkgs.firefox-unwrapped.override (old: {
-      onnxruntime = old.onnxruntime.override {
-        cudaSupport = false;
-        ncclSupport = false;
-      };
-    });
+  nixpkgs.config.packageOverrides = pkgs:
+    let
+      # pkgsNoCuda = pkgs.nixpkgsFun {
+      pkgsNoCuda =
+        # if !pkgs.config.cudaSupport then pkgs else
+        import pkgs.path {
+          # TODO: support cross?
+          localSystem.system = pkgs.stdenv.hostPlatform.system;
+          inherit (pkgs) overlays;
+          config = pkgs.config // { cudaSupport = false; };
+        };
+    in
+    lib.optionalAttrs pkgs.config.cudaSupport {
+      inherit (pkgsNoCuda)
+        firefox-unwrapped
+        openusd
+        vtk
+        ;
 
-    # openusd is too slow to build
-    opensubdiv = pkgs.opensubdiv.override {
-      cudaSupport = false;
+      # firefox-unwrapped = pkgs.firefox-unwrapped.override (old: {
+      #   onnxruntime = old.onnxruntime.override {
+      #     cudaSupport = false;
+      #     ncclSupport = false;
+      #   };
+      # });
+
+      # openusd is slow to build
+      # opensubdiv  = pkgs.opensubdiv.override { cudaSupport = false; };
+      # # pythonPackagesExtensions = pkgs.pythonPackagesExtensions ++ [
+      # #   (
+      # #     ps-final: ps-prev: {
+      # #       # openusd = ps-prev.openusd.overridePythonAttrs (old: {
+      # #       openusd = ps-prev.openusd.override (old: {
+      # #         opensubdiv = old.opensubdiv.override { cudaSupport = false; };
+      # #       });
+      # #     }
+      # #   )
+      # # ];
     };
 
-    # pythonPackagesExtensions = pkgs.pythonPackagesExtensions ++ [
-    #    (
-    #      ps-final: ps-prev: {
-    #        openusd = ps-prev.openusd.overridePythonAttrs (old: {
-    #          ...
-    #        });
-    #      }
-    #    )
-    #  ];
-  };
-
 }
 /* lib.mkIf (lib.versionAtLeast lib.version "24.11") { */
 (lib.optionalAttrs (lib.versionAtLeast lib.version "24.11") {