Use overlay

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

flake.nix

@@ -10,7 +10,10 @@
 
   outputs =
     inputs:
-    (
+    {
+      overlays.default = import ./overlay;
+    }
+    // (
       let
         system = "x86_64-linux";
 
@@ -22,8 +25,6 @@
         treefmt = inputs.treefmt-nix.lib.evalModule pkgs ./treefmt.nix;
       in
       {
-        lib.${system} = import ./lib { inherit pkgs; };
-
         formatter.${system} = treefmt.config.build.wrapper;
         checks.${system}.formatting = treefmt.config.build.check inputs.self;
       }

lib/default.nix

@@ -1,8 +0,0 @@
-{ pkgs, ... }:
-let
-  callPackage = pkgs.lib.callPackageWith { inherit pkgs; };
-in
-{
-  fetchers = callPackage ./fetchers { };
-  runtime = callPackage ./runtime { };
-}

lib/fetchers/default.nix

@@ -1,7 +0,0 @@
-{ pkgs, ... }:
-let
-  callPackage = pkgs.lib.callPackageWith { inherit pkgs; };
-in
-{
-  sshKnownHosts = callPackage ./sshKnownHosts { };
-}

lib/runtime/default.nix

@@ -1,7 +0,0 @@
-{ pkgs, ... }:
-let
-  callPackage = pkgs.lib.callPackageWith { inherit pkgs; };
-in
-{
-  merge = callPackage ./merge { };
-}

lib/runtime/merge/default.nix

@@ -1,7 +0,0 @@
-{ pkgs, ... }:
-let
-  callPackage = pkgs.lib.callPackageWith { inherit pkgs; };
-in
-{
-  keyValue = callPackage ./keyValue { };
-}

overlay/default.nix

@@ -0,0 +1,17 @@
+final: prev:
+let
+  callPackage = prev.lib.callPackageWith { pkgs = prev; };
+in
+{
+  lib = prev.lib.recursiveUpdate prev.lib {
+    fetchers = {
+      sshKnownHosts = callPackage ./fetchers/sshKnownHosts { };
+    };
+
+    runtime = {
+      merge = {
+        keyValue = callPackage ./runtime/merge/keyValue { };
+      };
+    };
+  };
+}