- Fix for BUG#1858 "SQL-Thread stops working when using optimize table":

we change THD::system_thread from a 'bool' to a bitmap to be able to
distinguish between delayed-insert threads and slave threads.
- Fix for BUG#1701 "Update from multiple tables" (one line in sql_parse.cc,
plus a new test rpl_multi_update.test). That's just adding an initialization.

sql/repl_failsafe.cc

@@ -52,6 +52,13 @@ static Slave_log_event* find_slave_event(IO_CACHE* log,
 					 const char* log_file_name,
 					 char* errmsg);
 
+/*
+  All of the functions defined in this file which are not used (the ones to
+  handle failsafe) are not used; their code has not been updated for more than
+  one year now so should be considered as BADLY BROKEN. Do not enable it.
+  The used functions (to handle LOAD DATA FROM MASTER, plus some small
+  functions like register_slave()) are working.
+*/
 
 static int init_failsafe_rpl_thread(THD* thd)
 {