Flake-enable the project

flake.nix

@@ -0,0 +1,68 @@
+{ inputs = {
+    nixpkgs.url = github:NixOS/nixpkgs/22.05;
+
+    utils.url = github:numtide/flake-utils;
+
+    flake-compat = {
+      url = "github:edolstra/flake-compat";
+      flake = false;
+    };
+  };
+
+  outputs = { nixpkgs, utils, ... }:
+    utils.lib.eachDefaultSystem (system:
+      let
+        overlay = pkgsNew: pkgsOld: {
+          haskellPackages = pkgsOld.haskellPackages.override (old: {
+            overrides =
+              pkgsNew.lib.fold pkgsNew.lib.composeExtensions (old.overrides or (_: _: { })) [
+                (pkgsNew.haskell.lib.packagesFromDirectory {
+                  directory = ./nix;
+                })
+                (haskellPackagesNew: haskellPackagesOld: {
+                  nix-serve-ng =
+                    pkgsNew.haskell.lib.overrideCabal
+                      haskellPackagesOld.nix-serve-ng
+                      (old: {
+                        executableSystemDepends = (old.executableSystemDepends or []) ++ [
+                          pkgsNew.boost.dev
+                        ];
+                      });
+                })
+              ];
+          });
+
+          nix-serve-ng =
+            pkgsNew.haskell.lib.justStaticExecutables
+              pkgsNew.haskellPackages.nix-serve-ng;
+        };
+
+        pkgs = import nixpkgs {
+          config = { };
+
+          overlays = [ overlay ];
+
+          inherit system;
+        };
+
+        inherit (pkgs) nix-serve-ng;
+
+      in
+        rec {
+          packages.default = nix-serve-ng;
+
+          defaultPackage = packages.default;
+
+          apps.default = {
+            type = "app";
+
+            program = "${nix-serve-ng}/bin/nix-serve-ng";
+          };
+
+          defaultApp = apps.default;
+
+          devShells.default = pkgs.haskellPackages.nix-serve-ng.env;
+
+          devShell = devShells.default;
+        });
+}