Do not use static GTypeInfo and GInterfaceInfo

Either g_type_register_static_simple (used by G_DEFINE_TYPE_EXTENDED)
and G_IMPLEMENT_INTERFACE use automatic variables for GTypeInfo and
GInterfaceInfo structs, while tutorials and source code often use
static variables. This commit consistently adopts the former method.

https://bugzilla.gnome.org/show_bug.cgi?id=600158

modules/other/gail/libgail-util/gailtextutil.c

@@ -46,7 +46,7 @@ gail_text_util_get_type(void)
 
   if (!type)
     {
-      static const GTypeInfo tinfo =
+      const GTypeInfo tinfo =
       {
         sizeof (GailTextUtilClass),
         (GBaseInitFunc) NULL, /* base init */