refactor: automatic options for overlays, fix build

nixosModules/nixpkgs-overlays.nix

@@ -0,0 +1,33 @@
+{
+  lib,
+  config,
+  self,
+  ...
+}:
+{
+  options.my.overlays = {
+    enableAll = lib.mkEnableOption "all nixpkgs overlays";
+  }
+  // lib.mapAttrs (_: _: {
+    enable = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+    };
+  }) self.overlays;
+
+  config = lib.mkMerge (
+    [
+      {
+        my.overlays = lib.mapAttrs (_: _: {
+          enable = lib.mkDefault config.my.overlays.enableAll;
+        }) self.overlays;
+      }
+    ]
+    ++ lib.mapAttrsToList (
+      name: overlay:
+      lib.mkIf config.my.overlays.${name}.enable {
+        nixpkgs.overlays = [ overlay ];
+      }
+    ) self.overlays
+  );
+}