[mutter] wayland/tablet: Fix warnings when native backend is disabled

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 8f2680c6128ef238ecfd6c617ffb9df8ec781947
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Aug 17 13:58:31 2018 +0200

    wayland/tablet: Fix warnings when native backend is disabled

 src/wayland/meta-wayland-tablet-pad-group.c | 2 +-
 src/wayland/meta-wayland-tablet-pad.c       | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/src/wayland/meta-wayland-tablet-pad-group.c b/src/wayland/meta-wayland-tablet-pad-group.c
index 93d5eb3f2..583fa0999 100644
--- a/src/wayland/meta-wayland-tablet-pad-group.c
+++ b/src/wayland/meta-wayland-tablet-pad-group.c
@@ -122,9 +122,9 @@ gboolean
 meta_wayland_tablet_pad_group_has_button (MetaWaylandTabletPadGroup *group,
                                           guint                      button)
 {
+#ifdef HAVE_NATIVE_BACKEND
   MetaBackend *backend = meta_get_backend ();
 
-#ifdef HAVE_NATIVE_BACKEND
   if (META_IS_BACKEND_NATIVE (backend))
     {
       struct libinput_device *libinput_device;
diff --git a/src/wayland/meta-wayland-tablet-pad.c b/src/wayland/meta-wayland-tablet-pad.c
index 7c7d880b6..ed31e236f 100644
--- a/src/wayland/meta-wayland-tablet-pad.c
+++ b/src/wayland/meta-wayland-tablet-pad.c
@@ -131,7 +131,9 @@ MetaWaylandTabletPad *
 meta_wayland_tablet_pad_new (ClutterInputDevice    *device,
                              MetaWaylandTabletSeat *tablet_seat)
 {
+#ifdef HAVE_NATIVE_BACKEND
   MetaBackend *backend = meta_get_backend ();
+#endif
   MetaWaylandTabletPad *pad;
   guint n_elems, i;