chore: add flake for development with Nix (#5509)

flake.lock

@@ -0,0 +1,41 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1659877975,
+        "narHash": "sha256-zllb8aq3YO3h8B/U0/J1WBgAL8EX5yWf5pMj3G0NAmc=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "c0e246b9b83f637f4681389ecabcb2681b4f3af0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1660639432,
+        "narHash": "sha256-2WDiboOCfB0LhvnDVMXOAr8ZLDfm3WdO54CkoDPwN1A=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "6c6409e965a6c883677be7b9d87a95fab6c3472e",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,25 @@
+{
+  description = "code-server";
+
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem
+      (system:
+        let pkgs = nixpkgs.legacyPackages.${system};
+            nodejs = pkgs.nodejs-16_x;
+            yarn' = pkgs.yarn.override { inherit nodejs; };
+        in {
+          devShells.default = pkgs.mkShell {
+            nativeBuildInputs = with pkgs; [
+              nodejs yarn' python pkg-config git rsync jq moreutils
+            ];
+            buildInputs = with pkgs; (lib.optionals (!stdenv.isDarwin) [ libsecret ]
+                          ++ (with xorg; [ libX11 libxkbfile ])
+                          ++ lib.optionals stdenv.isDarwin [
+                            AppKit Cocoa CoreServices Security cctools xcbuild
+                          ]);
+          };
+        }
+      );
+}