lxappearance: remove gtk 2 support

gtk 2 is unmaintained upstream and is being removed from Nixpkgs where
possible. gtk 3 is already the default, so there's little reason to keep
the support around.

pkgs/by-name/lx/lxappearance/package.nix

@@ -6,12 +6,10 @@
   intltool,
   pkg-config,
   libx11,
-  gtk2,
   gtk3,
   libxslt,
   docbook_xsl,
   wrapGAppsHook3,
-  withGtk3 ? true,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
@@ -38,7 +36,7 @@ stdenv.mkDerivation (finalAttrs: {
 
   buildInputs = [
     libx11
-    (if withGtk3 then gtk3 else gtk2)
+    gtk3
   ];
 
   patches = [
@@ -47,7 +45,7 @@ stdenv.mkDerivation (finalAttrs: {
 
   env.XSLTPROC = lib.getExe' libxslt "xsltproc";
 
-  configureFlags = lib.optional withGtk3 "--enable-gtk3";
+  configureFlags = [ "--enable-gtk3" ];
 
   meta = {
     description = "Lightweight program for configuring the theme and fonts of gtk applications";

pkgs/top-level/aliases.nix

@@ -1451,6 +1451,7 @@ mapAliases {
   luminanceHDR = throw "'luminanceHDR' has been removed as it depended on EOL qt5 webengine and was unmaintained"; # Added 2026-04-17
   lunarvim = throw "'lunarvim' has been removed since it was abandoned upstream and relied on an older version of 'neovim' to work properly"; # Added 2026-02-05
   lunatic = throw "'lunatic' has been removed, as it is unmaintained"; # Added 2026-05-04
+  lxappearance-gtk2 = throw "'lxappearance-gtk2' was removed because it depended on the deprecated GTK2 engine. Consider using the GTK3-based 'lxappearance' instead."; # Added 2026-07-22
   lxd = throw "
     LXD has been removed from NixOS due to lack of Nixpkgs maintenance.
     Consider migrating or switching to Incus, or remove from your configuration.

pkgs/top-level/all-packages.nix

@@ -10195,11 +10195,6 @@ with pkgs;
 
   ### DESKTOPS/LXDE
 
-  lxappearance-gtk2 = callPackage ../by-name/lx/lxappearance/package.nix {
-    gtk2 = gtk2-x11;
-    withGtk3 = false;
-  };
-
   lxqt = recurseIntoAttrs (
     import ../desktops/lxqt {
       inherit pkgs;