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/fd.c b/server/fd.c
index 797f77f..d3143cd 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -163,6 +163,7 @@
     NULL,                     /* satisfied */
     no_signal,                /* signal */
     no_get_fd,                /* get_fd */
+    no_close_handle,          /* close_handle */
     fd_destroy                /* destroy */
 };
 
@@ -193,6 +194,7 @@
     NULL,                     /* satisfied */
     no_signal,                /* signal */
     no_get_fd,                /* get_fd */
+    no_close_handle,          /* close_handle */
     inode_destroy             /* destroy */
 };
 
@@ -224,6 +226,7 @@
     no_satisfied,               /* satisfied */
     no_signal,                  /* signal */
     no_get_fd,                  /* get_fd */
+    no_close_handle,            /* close_handle */
     no_destroy                  /* destroy */
 };