There are three Log_event::read_log_event() methods:
1. read the event image from IO_CACHE into String
2. create Log_event from the in-memory event image
3. read the event image from IO_CACHE and create Log_event

The 3rd was reading event image into memory and invoking the 2nd to
create Log_event. Now the 3rd also uses the 1st to read the event image
from IO_CACHE into memory, instead of duplicating its functionality.

remove my_crc_dbug_check (gdb can do it itself).
use 0 instead of my_checkum(0, 0, 0) - just as 10.0 does now.

Instead of encrypt(src, dst, key, iv) that encrypts all
data in one go, now we have encrypt_init(key,iv),
encrypt_update(src,dst), and encrypt_finish(dst).

This also causes collateral changes in the internal my_crypt.cc
encryption functions and in the encryption service.

There are wrappers to provide the old all-at-once encryption
functionality. But binlog events are often written piecewise,
they'll need the new api.

Rename reassociate to reset and create an inverse method release.
Method names are chosen to match std::unique_ptr methods.

make repeated cmake runs less verbose:
* remove few not very useful MESSAGE's
* only run pkg_check_modules() if there's no cached result
* only print QQGraph messages on the first run

Fix all cmake tests (including plugin) to use
MY_CHECK_AND_SET_COMPILER_FLAG. And fix that function
to be compatible with cmake 3.0. This way flag checks
are correctly cached (even in cmake 3.0) and properly reused.

It caused the following main.innodb_load_xa to fail.

referenced_by_foreign_key2(), needed for InnoDB to compile,
was taken from 10.0-galera

If a transaction T1 needs to wait for a transaction T2, T2's commit will
skip the normal binlog_commit_wait_usec delay, in order not to needlessly
stall throughput.

This works by checking if T2 is already ready to commit. If so, it is woken
up. If not, we set a flag in T2 so that when it gets ready to commit, it
will do so immediately.

But there was a potential race due to insufficient locking, if T2 gets ready
to commit just at the point where T1 does the check. If the race hits, the
wakeup (and early commit) of T2 might be lost.

The race is only theoretical (from code inspection, no known test case), but
seems best to fix it anyway, by properly locking LOCK_prepare_ordered around
the check.

MDEV-8725: Assertion `!(thd->rgi_slave && thd-> rgi_slave->did_mark_start_commit)' failed in ha_rollback_trans

The assertion is there to catch cases where we rollback while
mark_start_commit() is active. This can allow following event groups
to be replicated too early, causing conflicts.

But in this case, we have an _explicit_ ROLLBACK event in the binlog,
which should not assert.

We fix this by delaying the mark_start_commit() in the explicit
ROLLBACK case. It seems safest to delay this in ROLLBACK case anyway,
and there should be no reason to try to optimise this corner case.

and vcol_supported_sql_funcs_innodb. Moving the test for using CHARSET(),
COLLATION(), COERCIBILITY() in virtual column from
vcol_supported_sql_funcs_xxx to vcol_blocked_sql_funcs_xxx,
as these functions are not supported in virtual columns any longer.
Discussed with Sanja on IRC.

- If run with valgrind, mysqltest will now wait longer when syncronizing slave with master
- Ensure that we wait with cleanup() until slave thread has stopped.
- Added signal_thd_deleted() to signal close_connections() that all THD's has been freed.
- Check in handle_fatal_signal() that we don't use variables that has been freed.
- Increased some timeouts when run with --valgrind

Other things:
- Fixed wrong test in one_thread_per_connection_end() if galera is used.
- Removed not needed calls to THD_CHECK_SENTRY() when we are calling 'delete thd'.

Part 5: Removing calls to current_thd in net_read calls, creating fields,
        query_cache, acl and some other places where thd was available

MDEV-8722 The patch for MDEV-8688 disabled equal field propagation for temporal column and BETWEEN and IN
Item::cmp_context was inconsistently used in combination with cmp_type()
and result_type() in different places of the code. Fixed to use cmp_type()
in all places where cmp_context is involved, to avoid unexpected results
for temporal data types (which have result_type()==STRING_RESULT and
cmp_type==TIME_RESULT).

MDEV-6219: Server crashes in Bitmap<64u>::merge (this=0x180, map2=...) on 2nd execution of PS with INSERT .. SELECT, derived_merge

Problem: Not all permanent Item_direct_view_ref was in permanent list of used items of the view.

Solution: Detect creating permenent view/derived table reference and put them in the permanent list at once.

SELECT..WHERE varchar_column=DATE'2001-01-01' AND varchar_column='2001-01-01'

The fix for MDEV-8688 fixed MDEV-8680 as well. Just adding a test case.

          SELECT..WHERE varchar_column IN (1,2,3) AND varchar_column=' 1';

Item_func_in::compare_collation() and Item_func_between::compare_collation(),
and adding Item_func_opt_neg::compare_collation() instead.

parent Item_func_opt_neg. A pre-requisite patch for a number of
upcoming equal field propagation related bug fixes.

Note, the patch for MDEV-8661 unintentionally fixed MDEV-8694 as well,
as a side effect. Adding a real clear fix: implementing
Item_func_like::propagate_equal_fields() with comments.

- Part 4: Removing calls to sql_alloc() and sql_calloc()

Other things:
- Added current_thd in some places to make it clear that it's called (easier to remove later)
- Move memory allocation from Item_func_case::fix_length_and_dec() to Item_func_case::fix_fields()
- Added mem_root to some new calls
- Fixed some wrong UNINIT_VAR() calls
- Fixed a bug in generate_partition_syntax() in case of errors
- Added mem_root to argument to new thread_info
- Simplified my_parse_error() call in sql_yacc.yy

- Part 3: Adding mem_root to push_back() and push_front()

Other things:
- Added THD as an argument to some partition functions.
- Added memory overflow checking for XML tag's in read_xml()

MDEV-8679 Equal field propagation is not used for VARCHAR when it safely could