Implemented NtSignalAndWaitForSingleObject.

diff --git a/server/mailslot.c b/server/mailslot.c
index 7a6230f..4066e57 100644
--- a/server/mailslot.c
+++ b/server/mailslot.c
@@ -72,6 +72,7 @@
     default_fd_remove_queue,   /* remove_queue */
     default_fd_signaled,       /* signaled */
     no_satisfied,              /* satisfied */
+    no_signal,                 /* signal */
     mailslot_get_fd,           /* get_fd */
     mailslot_destroy           /* destroy */
 };
@@ -113,6 +114,7 @@
     NULL,                       /* remove_queue */
     NULL,                       /* signaled */
     NULL,                       /* satisfied */
+    no_signal,                  /* signal */
     mail_writer_get_fd,         /* get_fd */
     mail_writer_destroy         /* destroy */
 };