To make MySQL compatible with some ODBC applications, you can find
the AUTO_INCREMENT value for the last inserted row with the following query:
 SELECT * FROM tbl_name WHERE auto_col IS NULL.
This is done with a special code that replaces 'auto_col IS NULL' with
'auto_col = LAST_INSERT_ID'.
However this also resets the LAST_INSERT_ID to 0 as it uses it for a flag
so as to ensure that only the first SELECT ... WHERE auto_col IS NULL
after an INSERT has this special behaviour.
In order to avoid resetting the LAST_INSERT_ID a special flag is introduced
in the THD class. This flag is used to restrict the second and subsequent
SELECTs instead of LAST_INSERT_ID.


mysql-test/r/odbc.result:
  test suite for the bug
mysql-test/r/rpl_insert_id.result:
  test for the fix in replication
mysql-test/t/odbc.test:
  test suite for the bug
mysql-test/t/rpl_insert_id.test:
  test for the fix in replication
sql/sql_class.cc:
  initialize the flag
sql/sql_class.h:
  flag's declaration and set code when setting the last_insert_id
sql/sql_select.cc:
  the special flag is used instead of last_insert_id