kde5 service: use flattening kdeWrapper

nixos/modules/services/x11/desktop-managers/kde5.nix

@@ -31,12 +31,25 @@ in
         '';
       };
 
+      extraPackages = mkOption {
+        type = types.listOf types.package;
+        default = [];
+        description = ''
+          KDE packages that need to be installed system-wide.
+        '';
+      };
+
     };
 
   };
 
 
-  config = mkIf (xcfg.enable && cfg.enable) {
+  config = mkMerge [
+    (mkIf (cfg.extraPackages != []) {
+      environment.systemPackages = [ (kde5.kdeWrapper cfg.extraPackages) ];
+    })
+
+    (mkIf (xcfg.enable && cfg.enable) {
 
       warnings = optional config.services.xserver.desktopManager.kde4.enable
         "KDE 4 should not be enabled at the same time as KDE 5";
@@ -120,7 +133,6 @@ in
           kde5.kdecoration
           kde5.kdeplasma-addons
           kde5.kgamma5
-        kde5.khelpcenter
           kde5.khotkeys
           kde5.kinfocenter
           kde5.kmenuedit
@@ -133,7 +145,6 @@ in
           kde5.libkscreen
           kde5.libksysguard
           kde5.milou
-        kde5.oxygen
           kde5.plasma-integration
           kde5.polkit-kde-agent
           kde5.systemsettings
@@ -142,12 +153,10 @@ in
           kde5.plasma-workspace
           kde5.plasma-workspace-wallpapers
 
-        kde5.dolphin
           kde5.dolphin-plugins
           kde5.ffmpegthumbs
           kde5.kdegraphics-thumbnailers
           kde5.kio-extras
-        kde5.konsole
           kde5.print-manager
 
           # Install Breeze icons if available
@@ -179,6 +188,15 @@ in
         ++ lib.optional config.services.colord.enable pkgs.colord-kde
         ++ lib.optionals config.services.samba.enable [ kde5.kdenetwork-filesharing pkgs.samba ];
 
+      services.xserver.desktopManager.kde5.extraPackages =
+        [
+          kde5.khelpcenter
+          kde5.oxygen
+
+          kde5.dolphin
+          kde5.konsole
+        ];
+
       environment.pathsToLink = [ "/share" ];
 
       environment.etc = singleton {
@@ -186,9 +204,9 @@ in
         target = "X11/xkb";
       };
 
-    # Enable GTK applications to load SVG icons
       environment.variables =
         {
+          # Enable GTK applications to load SVG icons
           GST_PLUGIN_SYSTEM_PATH_1_0 =
             lib.makeSearchPath "/lib/gstreamer-1.0"
             (builtins.map (pkg: pkg.out) (with pkgs.gst_all_1; [
@@ -229,6 +247,7 @@ in
 
       security.pam.services.kde = { allowNullPassword = true; };
 
-  };
+    })
+  ];
 
 }