updated for version 7.4.083
Problem:    It's hard to avoid adding a used pattern to the search history.
Solution:   Add the ":keeppatterns" modifier. (Christian Brabandt)
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 7ec47c7..906eb8b 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -5498,6 +5498,9 @@
     if (hislen == 0)		/* no history */
 	return;
 
+    if (cmdmod.keeppatterns && histype == HIST_SEARCH)
+	return;
+
     /*
      * Searches inside the same mapping overwrite each other, so that only
      * the last line is kept.  Be careful not to remove a line that was moved