patch 7.4.793
Problem:    Can't specify when not to ring the bell.
Solution:   Add the 'belloff' option. (Christian Brabandt)
diff --git a/src/search.c b/src/search.c
index c9614ea..4905a49 100644
--- a/src/search.c
+++ b/src/search.c
@@ -2469,7 +2469,7 @@
     }
 
     if ((lpos = findmatch(NULL, NUL)) == NULL)	    /* no match, so beep */
-	vim_beep();
+	vim_beep(BO_MATCH);
     else if (lpos->lnum >= curwin->w_topline && lpos->lnum < curwin->w_botline)
     {
 	if (!curwin->w_p_wrap)