Bug 548967 - 1 bit mutex lock

Add support for a mutex lock that consumes only one bit of storage
inside of an integer on systems that support futexes.  Futex is emulated
(at a higher cost) on systems that don't have it -- but only in the
contended case.

glib/gthread.c

@@ -166,6 +166,7 @@ g_thread_init_glib (void)
   _g_rand_thread_init ();
   _g_main_thread_init ();
   _g_utils_thread_init ();
+  _g_futex_thread_init ();
 #ifdef G_OS_WIN32
   _g_win32_thread_init ();
 #endif