[mutter] build: Fix non-wayland builds

[Florian Müllner <fmuellner src gnome org>]

commit 2f30098ab5fd3d0b9af93b317df31d45e11e081f
Author: Chris Vine <vine35792468 gmail com>
Date:   Sat Mar 25 15:24:00 2017 +0000

    build: Fix non-wayland builds
    
    Add the necessary preprocessor guards that were missed in commits
    65e9c89ed9bf and 6d64123849 ...
    
    https://bugzilla.gnome.org/show_bug.cgi?id=780533

 src/compositor/compositor.c |    2 ++
 src/core/main.c             |    2 ++
 2 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/src/compositor/compositor.c b/src/compositor/compositor.c
index fc43713..9a69c66 100644
--- a/src/compositor/compositor.c
+++ b/src/compositor/compositor.c
@@ -388,7 +388,9 @@ meta_begin_modal_for_plugin (MetaCompositor   *compositor,
       meta_display_sync_wayland_input_focus (display);
       meta_display_cancel_touch (display);
 
+#ifdef HAVE_WAYLAND
       meta_dnd_wayland_handle_begin_modal (compositor);
+#endif
     }
 
   return TRUE;
diff --git a/src/core/main.c b/src/core/main.c
index 9b82ca7..dc1f1c4 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -443,11 +443,13 @@ calculate_compositor_configuration (MetaCompositorType *compositor_type,
 #endif /* HAVE_WAYLAND */
     *compositor_type = META_COMPOSITOR_TYPE_X11;
 
+#ifdef HAVE_WAYLAND
   if (opt_nested)
     {
       *backend_gtype = META_TYPE_BACKEND_X11_NESTED;
       return;
     }
+#endif /* HAVE_WAYLAND */
 
 #ifdef HAVE_NATIVE_BACKEND
   if (opt_display_server)