Problem is that FLUSH TABLES WITH READ LOCK first blocks threads from
starting new commits, then waits for running commits to complete. But
in-order parallel replication needs commits to happen in a particular
order, so this can easily deadlock.

To fix this problem, this patch introduces a way to temporarily pause
the parallel replication worker threads. Before starting FTWRL, we let
all worker threads complete in-progress transactions, and then
wait. Then we proceed to take the global read lock. Once the lock is
obtained, we unpause the worker threads. Now commits are blocked from
starting by the global read lock, so the deadlock will no longer occur.

Preparation patch, moving the GCO wait into a separate function, in
preparation for adding a separate wait phase for FLUSH TABLES WITH
READ LOCK.

Before, the Seconds_behind_master was updated already when an event
was queued for a worker thread to execute later. This might lead users
to interpret a low value as the slave being almost up to date with the
master, while in reality there might still be lots and lots of events
still queued up waiting to be applied by the slave.

See https://lists.launchpad.net/maria-developers/msg08958.html for
more detailed discussions.

* update *.result files
* fix XtraDB for Windows (again)

* OSX (mysqlimport freeing unallocated memory)
* Windows (didn't compile MSI)
* fulltest2 (innodb crashes in --embedded --big)

Just "Master" could be understood as the master IP or hostname and thus can
cause confusion to db admins. "Master connection name" clearly states that
the log line contains connection name in the (possibly) multi-master setup.

it was never doing anything anyway

make_cond_for_info_schema() does preserve outer fields

MDEV-8685 MariaDB fails to decode Anonymous_GTID entries
MDEV-5705 Replication testing: 5.6->10.0

- Ignoring GTID events from MySQL 5.6+ (Allows replication from MySQL 5.6+ with GTID enabled)
- Added ignorable events from MySQL 5.6
- mysqlbinlog now writes information about GTID and ignorable events.
- Added more information in error message when replication stops because of wrong information in binary log.
- Fixed wrong test when write_on_release() should flush cache.

(even when configured with --binlog-format=statement).
Before we got an error on the slave and the slave stopped if the master
was configured with --binlog-format=mixed or --binlog-format=row.

When we calculate max_key_len for RANGE_OPT_PARAM::min_key/max_key, take
into account that QUICK_RANGE::QUICK_RANGE for some reason assumes
that there is one more byte there:

      max_key((uchar*) sql_memdup(max_key_arg,max_length_arg+1)),

EXPLAIN INSERT ... SELECT tried to use SELECT's execution path. This
caused a collection of problems:
- SELECT_DESCRIBE flag was not put into select_lex->options, which
  means it was not in JOIN::select_options either (except for the first
  member of the UNION).
- This caused UNION members to be executed. They would attempt to write
  join output rows to the output.
- (Actual cause of the crash) second join sibling would call
  result->send_eof() when finished execution. Then,
  Explain_query::print_explain would attempt to write to query output
  again, and cause an assertion due to non-empty query output.

Substitute into transformed subselects original left expression and than register its change in case it was substituted.

MDEV-7565: Server crash with Signal 6 (part 2)

followup test suite and its fix.

Problem was in rewriting left expression which had 2 references on it. Solved with making subselect reference main.

Item_in_optimized can have not Item_in_subselect reference in left part so type casting with no check is dangerous.

Item::cols() should be checked after Item::fix_fields().

Preparation of subselect moved earlier (before checks which needs it prepared).

[EXPLAIN] INSERT .. SELECT creates a select_insert object.
select_insert calls handler->start_bulk_insert() during
initialization.

For MyISAM/Aria this requires that a matching call to
handler->end_bulk_insert() call is made.

Regular INSERT .. SELECT accomplishes this by calling either
select_result->send_eof() or select_result->abort_result_set().

EXPLAIN INSERT ... SELECT didn't call either, which resulted in
improper de-initializaiton of handler object. Make it call
abort_result_set(), which invokes handler->end_bulk_insert().

Corrected variable name in dead code for consistency.

Patch contributed by Michal Hrusecky.

Fixed unclean prototype declaration. According to ISO/IEC 9899:TC2:
...
10. The special case of an unnamed parameter of type void as the only item in
    the list specifies that the function has no parameters.
...
14. An identifier list declares only the identifiers of the parameters of the
    function. An empty list in a function declarator that is part of a
    definition of that function specifies that the function has no parameters.
    The empty list in a function declarator that is not part of a definition of
    that function specifies that no information about the number or types of the
    parameters is supplied. 124)
...
6.11.6 Function declarators

The use of function declarators with empty parentheses (not prototype-format
parameter type declarators) is an obsolescent feature.
...

Patch contributed by Michal Hrusecky.

MDEV-8845: Table disappear after modifying FK

Added test case.