Merge Konstantin's patch and add a test case.

failed"

Do not assume that SQL prepared statements always run in text protocol.
When invoked from a stored procedure, which is itself invoked
by means of prepared CALL statement, the protocol may be binary.
Juggle with the protocol only when we want to change it
to binary in COM_STMT_EXECUTE, COM_STMT_PREPARE.

This is a backport from 5.4/6.0, where the bug was fixed
as part of WL#4264 "Backup: Stabilize Service Interface" 

Fixed the following problems:
1. cmake 2.6 warning because of a changed default on
how the dependencies to libraries with a specified 
path are resolved.
Fixed by requiring cmake 2.6.
2. Removed an obsolete pre-NT4 hack including defining
Windows system defines to alter the behavior of windows.h.
3. Disabled warning C4065 on compiling sql_yacc.cc because
of a know incompatibility in some of the newer bison binaries.

          match against.


Server crashes when executing prepared statement with duplicating
MATCH() function calls in SELECT and ORDER BY expressions, e.g.:
SELECT MATCH(a) AGAINST('test') FROM t1 ORDER BY MATCH(a) AGAINST('test')

This query gets optimized by the server, so the value returned
by MATCH() from the SELECT list is reused for ORDER BY purposes.
To make this optimization server is comparing items from
SELECT and ORDER BY lists. We were getting server crash because
comparision function for MATCH() item is not intended to be called
at this point of execution.

In 5.0 and 5.1 this problem is workarounded by resetting MATCH()
item to the state as it was during PREPARE.

In 6.0 correct comparision function will be implemented and
duplicating MATCH() items from the ORDER BY list will be
optimized.

"create as select" (innodb table)

Problem: code constructing "CREATE TABLE..." statement
doesn't take into account that current database is not set
in some cases. That may lead to a server crash.

Fix: check if current database is set.

without error

When using quick access methods for searching rows in UPDATE or 
DELETE there was no check if a fatal error was not already sent 
to the client while evaluating the quick condition.
As a result a false OK (following the error) was sent to the 
client and the error was thus transformed into a warning.

Fixed by checking for errors sent to the client during 
SQL_SELECT::check_quick() and treating them as real errors.

Fixed a wrong test case in group_min_max.test
Fixed a wrong return code in mysql_update() and mysql_delete()

            mutually-nested subqueries

Queries of the form

  SELECT * FROM (SELECT 1) AS t1,
                (SELECT 2) AS t2,...
                (SELECT 32) AS t32

caused the "Too high level of nesting for select" error
as if the query has a form

  SELECT * FROM (SELECT 1 FROM (SELECT 2 FROM (SELECT 3 FROM...


The table_factor parser rule has been modified to adjust
the LEX::nest_level variable value after every derived table.

Remove commented-out test case. It has been moved to innodb_bug21704.test

  sort_buffer_size cannot allocate

The NULL return from tree_insert() (on low memory) was not
checked for in Item_func_group_concat::add(). As a result
on low memory conditions a crash happens.

Fixed by properly checking the return code.

1. BUG#21704 - Renaming column does not update FK definition

2. Changes in mysql-test/include/mtr_warnings.sql so that the testcase
   for BUG#21704 doesn't fail because of the warnings generated.

Detailed revision comments:

r5488 | vasil | 2009-07-09 19:16:44 +0300 (Thu, 09 Jul 2009) | 13 lines
branches/5.1:

Fix Bug#21704 Renaming column does not update FK definition

by checking whether a column that participates in a FK definition is being
renamed and denying the ALTER in this case.

The patch was originally developed by Davi Arnaut <Davi.Arnaut@Sun.COM>:
http://lists.mysql.com/commits/77714
and was later adjusted to conform to InnoDB coding style by me (Vasil),
I also added some more comments and moved the bug specific mysql-test to
a separate file to make it more manageable and flexible.

            and base tables 

myrg_attach_children() could reuse a buffer that was allocated 
previously based on a definition of a child table. The problem 
was that the child's definition might have been changed, so 
reusing the buffer could lead to crashes or valgrind errors 
under some circumstances. 
 
Fixed by changing myrg_attach_children() so that the 
rec_per_key_part buffer is reused only when the child table
have not changed, and reallocated otherwise (the old buffer is 
deallocated if necessary).