geoclue2: add dbus service

nixos/modules/module-list.nix

@@ -99,6 +99,7 @@
   ./services/databases/virtuoso.nix
   ./services/databases/monetdb.nix
   ./services/desktops/accountservice.nix
+  ./services/desktops/geoclue2.nix
   ./services/desktops/gnome3/at-spi2-core.nix
   ./services/desktops/gnome3/evolution-data-server.nix
   ./services/desktops/gnome3/gnome-documents.nix

nixos/modules/services/desktops/geoclue2.nix

@@ -0,0 +1,39 @@
+# GeoClue 2 daemon.
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.geoclue2 = {
+
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to enable GeoClue 2 daemon, a DBus service
+          that provides location informationfor accessing.
+        '';
+      };
+
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf config.services.geoclue2.enable {
+
+    environment.systemPackages = [ pkgs.geoclue2 ];
+
+    services.dbus.packages = [ pkgs.geoclue2 ];
+
+  };
+
+}

nixos/modules/services/x11/desktop-managers/gnome3.nix

@@ -50,6 +50,7 @@ in {
     security.polkit.enable = true;
     services.udisks2.enable = true;
     services.accounts-daemon.enable = true;
+    services.geoclue2.enable = mkDefault true;
     services.gnome3.at-spi2-core.enable = true;
     services.gnome3.evolution-data-server.enable = true;
     services.gnome3.gnome-documents.enable = mkDefault true;