Index: b/gtk/a11y/gtkaccessibility.c
===================================================================
--- a/gtk/a11y/gtkaccessibility.c
+++ b/gtk/a11y/gtkaccessibility.c
@@ -989,7 +989,10 @@ _gtk_accessibility_init (void)
   do_window_event_initialization ();
 
 #ifdef GDK_WINDOWING_X11
+  GLogWriterOutput mushrooms_null_writer () { return G_LOG_WRITER_HANDLED; }
+  g_log_set_writer_func (mushrooms_null_writer, NULL, NULL);
   atk_bridge_adaptor_init (NULL, NULL);
+  g_log_set_writer_func (g_log_writer_default, NULL, NULL);
 #endif
 
   atk_misc_instance = g_object_new (GTK_TYPE_MISC_IMPL, NULL);