diff --git a/gdk/gdkenumtypes.c.template b/gdk/gdkenumtypes.c.template
index dcafd8d251..df9edfefa1 100644
--- a/gdk/gdkenumtypes.c.template
+++ b/gdk/gdkenumtypes.c.template
@@ -12,21 +12,26 @@
 GType
 @enum_name@_get_type (void)
 {
-    static GType etype = 0;
-    if (G_UNLIKELY(etype == 0)) {
-        static const G@Type@Value values[] = {
+  static volatile gsize g_define_type_id__volatile = 0;
+
+  if (g_once_init_enter (&g_define_type_id__volatile))
+    {
+      static const G@Type@Value values[] = {
 /*** END value-header ***/
 
 /*** BEGIN value-production ***/
-            { @VALUENAME@, "@VALUENAME@", "@valuenick@" },
+        { @VALUENAME@, "@VALUENAME@", "@valuenick@" },
 /*** END value-production ***/
 
 /*** BEGIN value-tail ***/
-            { 0, NULL, NULL }
-        };
-        etype = g_@type@_register_static (g_intern_static_string ("@EnumName@"), values);
+        { 0, NULL, NULL }
+      };
+      GType g_define_type_id =
+        g_@type@_register_static (g_intern_static_string ("@EnumName@"), values);
+      g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
     }
-    return etype;
+
+  return g_define_type_id__volatile;
 }
 
 /*** END value-tail ***/
diff --git a/gtk/gtkprivatetypebuiltins.c.template b/gtk/gtkprivatetypebuiltins.c.template
index db65d1efd6..2565208bfc 100644
--- a/gtk/gtkprivatetypebuiltins.c.template
+++ b/gtk/gtkprivatetypebuiltins.c.template
@@ -14,21 +14,26 @@
 GType
 _@enum_name@_get_type (void)
 {
-    static GType etype = 0;
-    if (G_UNLIKELY(etype == 0)) {
-        static const G@Type@Value values[] = {
+  static volatile gsize g_define_type_id__volatile = 0;
+
+  if (g_once_init_enter (&g_define_type_id__volatile))
+    {
+      static const G@Type@Value values[] = {
 /*** END value-header ***/
 
 /*** BEGIN value-production ***/
-            { @VALUENAME@, "@VALUENAME@", "@valuenick@" },
+        { @VALUENAME@, "@VALUENAME@", "@valuenick@" },
 /*** END value-production ***/
 
 /*** BEGIN value-tail ***/
-            { 0, NULL, NULL }
-        };
-        etype = g_@type@_register_static (g_intern_static_string ("@EnumName@"), values);
+        { 0, NULL, NULL }
+      };
+      GType g_define_type_id =
+        g_@type@_register_static (g_intern_static_string ("@EnumName@"), values);
+      g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
     }
-    return etype;
+
+  return g_define_type_id__volatile;
 }
 
 /*** END value-tail ***/
diff --git a/gtk/gtktypebuiltins.c.template b/gtk/gtktypebuiltins.c.template
index fbd21db368..f4d748b7b9 100644
--- a/gtk/gtktypebuiltins.c.template
+++ b/gtk/gtktypebuiltins.c.template
@@ -13,21 +13,26 @@
 GType
 @enum_name@_get_type (void)
 {
-    static GType etype = 0;
-    if (G_UNLIKELY(etype == 0)) {
-        static const G@Type@Value values[] = {
+  static volatile gsize g_define_type_id__volatile = 0;
+
+  if (g_once_init_enter (&g_define_type_id__volatile))
+    {
+      static const G@Type@Value values[] = {
 /*** END value-header ***/
 
 /*** BEGIN value-production ***/
-            { @VALUENAME@, "@VALUENAME@", "@valuenick@" },
+        { @VALUENAME@, "@VALUENAME@", "@valuenick@" },
 /*** END value-production ***/
 
 /*** BEGIN value-tail ***/
-            { 0, NULL, NULL }
-        };
-        etype = g_@type@_register_static (g_intern_static_string ("@EnumName@"), values);
+        { 0, NULL, NULL }
+      };
+      GType g_define_type_id =
+        g_@type@_register_static (g_intern_static_string ("@EnumName@"), values);
+      g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
     }
-    return etype;
+
+  return g_define_type_id__volatile;
 }
 
 /*** END value-tail ***/