add: flake.nix and other required files for nix build

default.nix

@@ -0,0 +1,41 @@
+{ lib
+, fetchFromGitHub
+, buildGoModule
+}:
+buildGoModule rec {
+  pname = "clash-meta";
+  version = "1.13.1";
+
+  src = fetchFromGitHub {
+    owner = "MetaCubeX";
+    repo = "Clash.Meta";
+    rev = "1684756b79a232ee8f875bcfd87371f5c0ef066b";
+    sha256 = "sha256-7g/Wcll0w4EhPI+KodtLHINqaR2larQNnP9YAsgNiN4=";
+  };
+
+  vendorSha256 = "sha256-7HjYcoqWA5gvPUc5psCgy0UTc17CBzBJ/OiGvII/iBA=";
+
+  # Do not build testing suit
+  excludedPackages = [ "./test" ];
+
+  CGO_ENABLED = 0;
+
+  ldflags = [
+    "-s"
+    "-w"
+    "-X github.com/Dreamacro/clash/constant.Version=${version}"
+  ];
+
+  # network required
+  doCheck = false;
+
+  postInstall = ''
+    mv $out/bin/clash $out/bin/clash-meta
+  '';
+
+  meta = with lib; {
+    description = "Another Clash Kernel";
+    homepage = "https://github.com/MetaCubeX/Clash.Meta";
+    license = licenses.gpl3Only;
+  };
+}

flake.lock

@@ -0,0 +1,43 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1664614409,
+        "narHash": "sha256-5y+zhLMzc/k4NYnCfW+seM9oaNuUI/UeGMGPFRj8cR0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "b746456c6f6ef8404ef6011df5eceba8644c49a9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "master",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "utils": "utils"
+      }
+    },
+    "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"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,19 @@
+{
+  description = "Another Clash Kernel";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/master";
+
+  inputs.utils.url = "github:numtide/flake-utils";
+
+  outputs = { self, nixpkgs, utils }:
+    (utils.lib.eachDefaultSystem
+      (system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+        in
+
+        {
+          defaultPackages = pkgs.callPackage ./. { };
+        })
+    );
+}