and some SP-related cleanups.

- We don't have separate stage for calculation of list of tables
  to be prelocked and doing implicit LOCK/UNLOCK any more.
  Instead we calculate this list at open_tables() and do implicit
  LOCK in lock_tables() (and UNLOCK in close_thread_tables()).
  Also now we support cases when same table (with same alias) is
  used several times in the same query in SP.

- Cleaned up execution of SP. Moved all common code which handles
  LEX and does preparations before statement execution or complex
  expression evaluation to auxilary sp_lex_keeper class. Now 
  all statements in SP (and corresponding instructions) that
  evaluate expression which can contain subquery have their
  own LEX.

into mysql.com:/home/mydev/mysql-4.1-4100

into mysql.com:/home/mydev/mysql-4.1-4100

Added a missing comma.

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

into serg.mylan:/usr/home/serg/Abk/mysql-4.0

into mysql.com:/home/jimw/my/mysql-4.1-clean

into mysql.com:/home/jimw/my/mysql-4.1-clean

into mysql.com:/home/jimw/my/mysql-4.1-clean

into mysql.com:/home/jimw/my/mysql-5.0-clean

into gluh.mysql.r18.ru:/home/gluh/MySQL-MERGE/mysql-5.0

into mysql.com:/home/jimw/my/mysql-5.0-clean

into gluh.mysql.r18.ru:/home/gluh/MySQL-MERGE/mysql-5.0

  Work around the AIX 5.1 security patch ML7 problem in errno when it should be EEXIST

  Work around the AIX 5.1 ML7 patch problem in errno at a higher level, in srv0start.c
os0file.c:
  Revert the AIX patch here

into hundin.mysql.fi:/home/heikki/mysql-4.1

  AIX 5.1 after security patch ML7 seems to contain a bug that instead of EEXIST it sets errno to 0 if a file creation fails because the file already exists. Work around that bug by interpreting errno 0 in AIX as EEXIST.

will not cause "make" to fail.

 and bug#8849 "problem with insert statement with table alias's": 
make equality propagation work in stored procedures and prepared 
statements.
Equality propagation can change AND/OR structure of ON expressions,
so the fix is to provide each execution of PS/SP with it's own
copy of AND/OR tree. We have been doing that already for WHERE clauses,
now ON clauses are also copied.

into mysql.com:/M50/mysql-5.0

into mysql.com:/space/pekka/ndb/version/my41

See mysqldump.test diff for more details

into mysql.com:/usr/home/ram/work/5.0