Added a close_handle method to the object operations, and use it to
implement registry notifications and the strange behavior of
CloseHandle on winstation/desktop handles.

diff --git a/server/queue.c b/server/queue.c
index 38e5d67..d827c0f 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -148,6 +148,7 @@
     msg_queue_satisfied,       /* satisfied */
     no_signal,                 /* signal */
     no_get_fd,                 /* get_fd */
+    no_close_handle,           /* close_handle */
     msg_queue_destroy          /* destroy */
 };
 
@@ -162,6 +163,7 @@
     NULL,                         /* satisfied */
     no_signal,                    /* signal */
     no_get_fd,                    /* get_fd */
+    no_close_handle,              /* close_handle */
     thread_input_destroy          /* destroy */
 };