don't use linux-specific tools on darwin

flake.nix

@@ -33,28 +33,28 @@
 
       # `nix develop`
       devShell = pkgs.mkShell {
-        nativeBuildInputs = with pkgs; [
-          cacert
-          cargo
-          cargo-edit
-          cargo-flamegraph
-          cargo-outdated
-          cargo-release
-          cargo-tarpaulin
-          cargo-watch
-          clippy
-          git
-          hotspot
-          llvmPackages_13.llvm
-          nixpkgs-fmt
-          openssh
-          openssl
-          perf-tools
-          pkg-config
-          rustc
-          rustfmt
-          statix
-        ];
+        nativeBuildInputs = with pkgs;
+          [
+            cacert
+            cargo
+            cargo-edit
+            cargo-flamegraph
+            cargo-outdated
+            cargo-release
+            cargo-tarpaulin
+            cargo-watch
+            clippy
+            git
+            llvmPackages_13.llvm
+            nixpkgs-fmt
+            openssh
+            openssl
+            pkg-config
+            rustc
+            rustfmt
+            statix
+          ]
+          ++ (lib.optional stdenv.isLinux [pkgs.hotspot pkgs.perf-tools]);
         RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
       };
     });