clean up devShell templates

DEPENDENCIES.md

@@ -11,26 +11,33 @@ get them, if your system isn't here, add it!
 You can add this `shell.nix` to your project and use it by running `nix-shell`:
 
 ```nix
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import <nixpkgs> { } }:
 
-pkgs.mkShell rec {
-  buildInputs = with pkgs; [
-    expat
-    fontconfig
-    freetype
-    freetype.dev
-    libGL
-    pkg-config
-    xorg.libX11
-    xorg.libXcursor
-    xorg.libXi
-    xorg.libXrandr
-    wayland
+let
+  dlopenLibraries = with pkgs; [
     libxkbcommon
+
+    # GPU backend
+    vulkan-loader
+    # libGL
+
+    # Window system
+    wayland
+    # xorg.libX11
+    # xorg.libXcursor
+    # xorg.libXi
+  ];
+in pkgs.mkShell {
+  nativeBuildInputs = with pkgs; [
+    cargo
+    rustc
   ];
 
-  LD_LIBRARY_PATH =
-    builtins.foldl' (a: b: "${a}:${b}/lib") "${pkgs.vulkan-loader}/lib" buildInputs;
+  # additional libraries that your project
+  # links to at build time, e.g. OpenSSL
+  buildInputs = [];
+
+  env.RUSTFLAGS = "-C link-arg=-Wl,-rpath,${pkgs.lib.makeLibraryPath dlopenLibraries}";
 }
 ```
 
@@ -39,43 +46,45 @@ Alternatively, you can use this `flake.nix` to create a dev shell, activated by
 ```nix
 {
   inputs = {
-    nixpkgs.url = "nixpkgs/nixos-unstable";
-    flake-utils.url = "github:numtide/flake-utils";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    systems.url = "github:nix-systems/default";
   };
 
-  outputs = {
-    nixpkgs,
-    flake-utils,
-    ...
-  }:
-    flake-utils.lib.eachDefaultSystem (
-      system: let
-        pkgs = import nixpkgs {
-          inherit system;
-        };
+  outputs = { nixpkgs, systems, ... }:
+    let
+      eachSystem = nixpkgs.lib.genAttrs (import systems);
+      pkgsFor = nixpkgs.legacyPackages;
+    in {
+      devShells = eachSystem (system:
+        let
+          pkgs = pkgsFor.${system};
+          dlopenLibraries = with pkgs; [
+            libxkbcommon
 
-        buildInputs = with pkgs; [
-          expat
-          fontconfig
-          freetype
-          freetype.dev
-          libGL
-          pkg-config
-          xorg.libX11
-          xorg.libXcursor
-          xorg.libXi
-          xorg.libXrandr
-          wayland
-          libxkbcommon
-        ];
-      in {
-        devShells.default = pkgs.mkShell {
-          inherit buildInputs;
+            # GPU backend
+            vulkan-loader
+            # libGL
 
-          LD_LIBRARY_PATH =
-            builtins.foldl' (a: b: "${a}:${b}/lib") "${pkgs.vulkan-loader}/lib" buildInputs;
-        };
-      }
-    );
+            # Window system
+            wayland
+            # xorg.libX11
+            # xorg.libXcursor
+            # xorg.libXi
+          ];
+        in {
+          default = pkgs.mkShell {
+            nativeBuildInputs = with pkgs; [
+              cargo
+              rustc
+            ];
+
+            # additional libraries that your project
+            # links to at build time, e.g. OpenSSL
+            buildInputs = [];
+
+            env.RUSTFLAGS = "-C link-arg=-Wl,-rpath,${nixpkgs.lib.makeLibraryPath dlopenLibraries}";
+          };
+        });
+    };
 }
 ```