diff --color -U 5 -r -Z -B ./org/gtk/a11y/gtkaccessibility.c ./mod/gtk/a11y/gtkaccessibility.c
--- a/gtk/a11y/gtkaccessibility.c	2017-10-02 18:00:49.000000000 +0200
+++ b/gtk/a11y/gtkaccessibility.c	2017-10-30 21:26:10.880336153 +0100
@@ -987,10 +987,13 @@
 
   _gtk_accessibility_override_atk_util ();
   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);
 }