Diff to actual 5.0-bugteam is revno: 2725 only

            leads to an assertion failure

Any run-time error in stored function (like recursive function
call or update of table that is already updating by statement
which invoked this stored function etc.) that was used in some
expression of the single-table UPDATE statement caused an
assertion failure.
Multiple-table UPDATE (as well as INSERT and both single- and
multiple-table DELETE) are not affected.

            an error

Even after the fix for bug 28701 visible behaviors of
SELECT FROM a view and SELECT FROM a regular table are
little bit different:

1. "SELECT FROM regular table USE/FORCE/IGNORE(non
   existent index)" fails with a "ERROR 1176 (HY000):
   Key '...' doesn't exist in table '...'"

2. "SELECT FROM view USING/FORCE/IGNORE(any index)" fails
   with a "ERROR 1221 (HY000): Incorrect usage of
   USE/IGNORE INDEX and VIEW".  OTOH "SHOW INDEX FROM
   view" always returns empty result set, so from the point
   of same behaviour view we trying to use/ignore non
   existent index.

To harmonize the behaviour of USE/FORCE/IGNORE(index)
clauses in SELECT from a view and from a regular table the
"ERROR 1221 (HY000): Incorrect usage of USE/IGNORE INDEX
and VIEW" message has been replaced with the "ERROR 1176
(HY000): Key '...' doesn't exist in table '...'" message
like for tables and non existent keys.

      
The SHOW VARIABLES LIKE .../SELECT @@/SELECT ... FROM INFORMATION_SCHEMA.VARIABLES
were assuming that all the system variables are in system charset (UTF-8).
However the variables that are settable through command line will have a different
character set (character_set_filesystem).
Fixed the server to remember the correct character set of basedir, datadir, tmpdir,
ssl, plugin_dir, slave_load_tmpdir, innodb variables; init_connect and init_slave 
variables and use it when processing data.

The bug is repeatable with latest(1.0.1) InnoDB plugin on Linux, Win,
If MySQL is compiled with valgrind there are errors about
using of uninitialized variable(orig_table).
The fix is to set field->orig_table correct value.

Reason for the failing test was that "SELECT count(*) from mysql.general_log;" was not always
the same number. That was fixed by "...count(*)>4..." as the minimal fulfilled condition.
As Bug 35371 was fixed the testcase with "log_output = 'FILE'" was enabled and changed to have
always the same result.

enable uncacheable flag if we update a view with check option
and check option has a subselect, otherwise, the check option
can be evaluated after the subselect was freed as independent
(See full_local in JOIN::join_free())

set DATE|DATETIME value to 0 if ALLOW_INVALID_DATES sql_mode is not enabled.

extended perror to enable printing of Win32 system errors

(no conflicts)

We pretended that TIMEDIFF() would always return positive results;
this gave strange results in comparisons of the TIMEDIFF(low,hi)<TIME(0)
type that rendered a negative result, but still gave false in comparison.
We also inadvertantly dropped the sign when converting times to
decimal.

CAST(time AS DECIMAL) handles signs of the times correctly.
TIMEDIFF() marked up as signed. Time/date comparison code switched to
signed for clarity.