feat(c): setup the flake

c/flake.nix

@@ -0,0 +1,48 @@
+{
+  description = "Templates for getting started with Aux";
+
+  inputs.nixpkgs.url = "github:auxolotl/nixpkgs/nixos-unstable";
+
+  outputs = { self, nixpkgs }:
+    let
+      forAllSystems =
+        function:
+        nixpkgs.lib.genAttrs [
+          "x86_64-linux"
+          "aarch64-linux"
+          "x86_64-darwin"
+          "aarch64-darwin"
+          "i686-linux"
+          "mipsel-linux"
+          "powerpc64le-linux"
+        ] (system: function nixpkgs.legacyPackages.${system});
+    in rec {
+      devShells.default = forAllSystems (pkgs:
+        pkgs.mkShell {
+          hardeningDisable = [ "fortify" ];
+          inputsFrom = pkgs.lib.attrsets.attrValues packages;
+        });
+
+      packages = forAllSystems (pkgs: rec {
+        default = hello;
+        hello = pkgs.stdenv.mkDerivation rec {
+          name = "hello";
+
+          src = ./.;
+          nativeBuildInputs = [ pkgs.gnumake ];
+
+          enableParallelBuilding = true;
+          V = 1;
+          installPhase = ''
+            install -D ${name} $out/bin/${name} --mode 0755
+          '';
+        };
+      });
+
+      apps = rec {
+        default = hello;
+        hello = builtins.mapAttrs
+          (name: value: "${value.hello}/bin/hello") packages;
+      };
+    };
+}