gtk3: make x11Support actually disable X11 dependencies

pkgs/development/libraries/gtk/3.x.nix

@@ -129,9 +129,15 @@ stdenv.mkDerivation (finalAttrs: {
     wayland-scanner
   ];
 
-  buildInputs = [
+  buildInputs =
+    lib.optionals (x11Support || waylandSupport) [
+      # TODO: Reorder me on `staging`.
       libxkbcommon
+    ]
+    ++ [
       (libepoxy.override { inherit x11Support; })
+    ]
+    ++ lib.optionals (x11Support || waylandSupport) [
       isocodes
     ]
     ++ lib.optionals trackerSupport [
@@ -139,9 +145,7 @@ stdenv.mkDerivation (finalAttrs: {
     ];
   #TODO: colord?
 
-  propagatedBuildInputs =
-    with xorg;
-    [
+  propagatedBuildInputs = [
     at-spi2-atk
     atk
     cairo
@@ -150,6 +154,10 @@ stdenv.mkDerivation (finalAttrs: {
     gdk-pixbuf
     glib
     gsettings-desktop-schemas
+  ]
+  ++ lib.optionals x11Support (
+    with xorg;
+    [
       libICE
       libSM
       libXcomposite
@@ -159,6 +167,10 @@ stdenv.mkDerivation (finalAttrs: {
       libXi
       libXrandr
       libXrender
+    ]
+  )
+  ++ [
+    # TODO: Reorder me on `staging`.
     pango
   ]
   ++ lib.optionals waylandSupport [
@@ -167,7 +179,7 @@ stdenv.mkDerivation (finalAttrs: {
     wayland-protocols
   ]
   ++ lib.optionals xineramaSupport [
-      libXinerama
+    xorg.libXinerama
   ]
   ++ lib.optionals cupsSupport [
     cups