Add nix derivation

.gitignore

@@ -1,5 +1,5 @@
 /target
 **/*.rs.bk
 proptest-regressions/
-Cargo.lock
-.idea/
+.idea/
+result

default.nix

@@ -0,0 +1,35 @@
+{ pkgs ? import <nixpkgs> {
+    overlays = [
+      (import (fetchTarball "https://github.com/oxalica/rust-overlay/archive/master.tar.gz"))
+    ];
+  }
+}:
+with pkgs;
+let
+  agent = callPackage "${fetchgit {
+    url = "https://gitea.rixxc.de/rixxc/agent_harness.git";
+    rev = "d2154ade95b88fe90709cdb12a35da50e0ddb5ee";
+    hash = "sha256-low2S2z5vaFSS6ZdDVaxJdwBZk+mjXaG2zhConCWQPQ=";
+  }}/default.nix"
+    { inherit pkgs; };
+in
+rustPlatform.buildRustPackage
+{
+  name = "wireguard-agent";
+  src = nix-gitignore.gitignoreSource [ ] ./.;
+
+  nativeBuildInputs = [ 
+    (rust-bin.fromRustupToolchainFile ./rust-toolchain.toml)    
+    agent
+  ];
+
+  cargoLock = {
+    lockFile = ./Cargo.lock;
+  };
+
+  doCheck = false;
+
+  AGENT_PATH = "${agent}/bin/agent_harness";
+  KEY_FILE = "keyfile";
+  RUST_LOG = "debug";
+}

rust-toolchain.toml

@@ -0,0 +1,2 @@
+[toolchain]
+channel = "nightly"