Add Nix flake

and add result to .gitignore

flake.nix

@@ -0,0 +1,36 @@
+{
+	description = "Callisto, a featureful extension runtime for Lua 5.4";
+
+	inputs = {
+		nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+	};
+
+	outputs = { self, nixpkgs }:
+	let
+		forAllSystems = fn:
+			nixpkgs.lib.genAttrs [
+				"x86_64-linux"
+				"x86_64-darwin"
+				"aarch64-linux"
+			] (system:
+				fn (import nixpkgs {
+					inherit system;
+				})
+			);
+	in
+	{
+		packages = forAllSystems (pkgs: {
+			default = pkgs.stdenv.mkDerivation {
+				name = "callisto";
+				src = ./.;
+				buildPhase = ''
+					make
+				'';
+				installPhase = ''
+					mkdir -p $out/bin
+					make DESTDIR="$out" PREFIX=/ install
+				'';
+			};
+		});
+	};
+}