diff --git a/glib/gthread.c b/glib/gthread.c
index 2045ff0d2..a3f4b6ae0 100644
--- a/glib/gthread.c
+++ b/glib/gthread.c
@@ -288,6 +288,7 @@ guint64        (*g_thread_gettime) (void) = gettime;
 /* Global Variables {{{1 -------------------------------------------------- */
 
 static GSystemThread zero_thread; /* This is initialized to all zero */
+gboolean g_thread_use_default_impl = TRUE;
 
 /**
  * g_thread_supported: