nix: shell.nix works standalone again

flake.nix

@@ -24,6 +24,15 @@
         }));
     in
     {
-      devShells = forAllSystems (pkgs: { default = import ./shell.nix { inherit pkgs; }; });
+      devShells = forAllSystems
+        (pkgs: {
+          default = import ./shell.nix
+            {
+              inherit pkgs;
+              additionalBuildInputs = [
+                (pkgs.rust-bin.selectLatestNightlyWith (toolchain: toolchain.default))
+              ];
+            };
+        });
     };
 }

shell.nix

@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> { } }:
+{ pkgs ? import <nixpkgs> { }, additionalBuildInputs ? [ ] }:
 
 with pkgs;
 
@@ -18,8 +18,6 @@ mkShell rec {
 
     libxkbcommon # To use the wayland feature
     wayland
-
-    (rust-bin.selectLatestNightlyWith (toolchain: toolchain.default))
-  ];
+  ] ++ additionalBuildInputs;
   LD_LIBRARY_PATH = lib.makeLibraryPath buildInputs;
 }