After the ChangeSet 1.1892.20.1 2005/08/24 (Bug #12562) SYSDATE() is not an alias
   of NOW() and is unsafe for replication.
   `SYSDATE()' backward compatible aliasing clashes with the idea #12562 
   fix. To make it safe-replicatable we have to either use RBR or to restore
   the pre-5.0 style.
   --sysdate-is-now command line flag was introduced to provide backward compatibility.


sql/mysqld.cc:
  New option to force SYSDATE's backward compatible with 4.1 aliasing to NOW (not default)
sql/sql_class.h:
  new slot to fill at init time and check at parse
sql/sql_yacc.yy:
  calling NOW's branches when --sysdate-is-now
mysql-test/r/sysdate_is_now.result:
  New BitKeeper file ``mysql-test/r/sysdate_is_now.result''
mysql-test/t/sysdate_is_now-master.opt:
  New BitKeeper file ``mysql-test/t/sysdate_is_now-master.opt''
mysql-test/t/sysdate_is_now.test:
  New BitKeeper file ``mysql-test/t/sysdate_is_now.test''