include rust tools in shell instead of rustup

shell.nix

@@ -1,11 +1,16 @@
 {pkgs ? import <nixpkgs> {}}:
 pkgs.mkShell {
   nativeBuildInputs = with pkgs.buildPackages; [
-    rustup
+    rustc cargo gcc rustfmt clippy
+
     pkg-config
     xe
     lzma
     cargo-tarpaulin
     gnumake
+
+    # dotnet-sdk_8
   ];
+
+  RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
 }