Fix gio/gcancellable.c build when thread support is disabled

Signed-off-by: "Samuel Martin" <s.martin49@gmail.com>
---
--- a/gio/gcancellable.c	2013-05-14 23:08:25.514461348 +0200
+++ b/gio/gcancellable.c	2013-05-14 23:10:23.347789625 +0200
@@ -270,8 +270,10 @@ g_cancellable_reset (GCancellable *cance
   while (priv->cancelled_running)
     {
       priv->cancelled_running_waiting = TRUE;
+#if defined(G_THREADS_ENABLED)
       g_cond_wait (cancellable_cond,
                    g_static_mutex_get_mutex (& G_LOCK_NAME (cancellable)));
+#endif
     }
 
   if (priv->cancelled)
@@ -619,8 +621,10 @@ g_cancellable_disconnect (GCancellable
   while (priv->cancelled_running)
     {
       priv->cancelled_running_waiting = TRUE;
+#if defined(G_THREADS_ENABLED)
       g_cond_wait (cancellable_cond,
                    g_static_mutex_get_mutex (& G_LOCK_NAME (cancellable)));
+#endif
     }
 
   g_signal_handler_disconnect (cancellable, handler_id);