Rewrite nix-shell, use mold for the linker

shell.nix

@@ -1,32 +1,30 @@
 let
-  rust_overlay = import (builtins.fetchTarball https://github.com/oxalica/rust-overlay/archive/master.tar.gz);
-  nixpkgs = import <nixpkgs> { overlays = [ rust_overlay ]; };
-
-  rust = (nixpkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml).override {
-    extensions = [ "rust-analysis" "rust-src" "miri-preview" ];
+  rust_overlay = import (builtins.fetchTarball "https://github.com/oxalica/rust-overlay/archive/master.tar.gz");
+  pkgs = import <nixpkgs> { overlays = [ rust_overlay ]; };
+  
+  rust = (pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml).override {
+    extensions = [
+      "rust-analyzer"
+      "rust-src"
+      "miri-preview"
+    ];
   };
 in
-  with nixpkgs;
-  stdenv.mkDerivation rec {
-    name = "lyra_engine_dev";
-    nativeBuildInputs = [
-      pkg-config
-      openssl
-      wasm-pack
-      trunk
-      valgrind
-      heaptrack
-      mold
-      udev
-      lua5_4_compat
-      rust
-    ];
-    buildInputs = [
-      udev alsa-lib libGL gcc
-      vulkan-loader vulkan-headers vulkan-tools
-      xorg.libX11 xorg.libXcursor xorg.libXi xorg.libXrandr # To use the x11 feature
-      libxkbcommon wayland # To use the wayland feature
-      
-    ];
-    LD_LIBRARY_PATH = lib.makeLibraryPath buildInputs;
-  }
+pkgs.mkShell.override {
+  stdenv = pkgs.stdenvAdapters.useMoldLinker pkgs.clangStdenv;
+} rec {
+  buildInputs = [
+    rust 
+  ] ++ (with pkgs; [
+    pkg-config openssl udev
+    wasm-pack trunk
+    heaptrack valgrind 
+    lua5_4_compat
+    alsa-lib libGL
+    vulkan-loader vulkan-headers vulkan-tools
+    libxkbcommon wayland # To use the wayland feature
+    xorg.libX11 xorg.libXcursor xorg.libXi xorg.libXrandr # To use the x11 feature
+  ]);
+  LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath buildInputs;
+  #RUST_BACKTRACE = 1;
+}