merge with mysql-5.5.21

mysql-test/r/mysqld--help.result

@@ -775,6 +775,9 @@ The following options may be given as the first argument:
  for the complete list of valid sql modes
  --stack-trace       Print a symbolic stack trace on failure
  (Defaults to on; use --skip-stack-trace to disable.)
+ --stored-program-cache=# 
+ The soft upper limit for number of cached stored routines
+ for one connection.
  -s, --symbolic-links 
  Enable symbolic link support.
  --sync-binlog=#     Synchronously flush binary log to disk after every #th
@@ -1059,6 +1062,7 @@ slow-query-log FALSE
 sort-buffer-size 2097152
 sql-mode 
 stack-trace TRUE
+stored-program-cache 256
 symbolic-links FALSE
 sync-binlog 0
 sync-frm FALSE