backport from 10.0 the fix for:
  MDEV-5756 CMake option to build without thread pool

issue an error for unrecognized options in the [mysqld_safe] section of my.cnf
but don't abort the script

fix by Sriram Patil

IBUF_DUMMY table.

compression failures on insert buffer.

MySQL Bug#71095: Wrong results with PARTITION BY LIST COLUMNS()
MySQL Bug#72803: Wrong "Impossible where" with LIST partitioning
MDEV-6240: Wrong "Impossible where" with LIST partitioning
- Backprot the fix from MySQL Bug#71095.

- When traversing JOIN_TABs with first_linear_tab/next_linear_tab(), don't forget
  to enter the semi-join nest when it is the first table in the join order.
  Failure to do so could cause e.g. I_S tables not to be filled.

Item_func_min_max::get_date() did not clear ltime->year when returning a TIME value.

            server initialization

ER() macro was used during server initialization. It refers to
current_thd, which is not available that early.

Print error to error log in "lc-messages" locale.
Avoid duplicate error message during server initialization.

mysqld didn't fail to start if a compiled-in plugin failed to initialize
(--xxx=FORCE behaving as --xxx=ON)

Improve long semaphore wait output to include all semaphore waits
and try to find out if there is a sequence of waiters.

Add more status information if repeatable.

- Part #2. Fix obvious problems in the previous patch.

- Filesort has an optmization where it reads only columns that are 
  needed before the sorting is done.
- When ref(_or_null) is picked by the join optimizer, it may remove parts
  of WHERE clause that are guaranteed to be true.
- However, if we use quick select, we must put all of the range columns into the 
  read set. Not doing so will may cause us to fail to detect the end of the range.

Analysis: sync array output function, should make sure that all 
used pointers are valid before using them.

This is not a real fix, instead try to gather additional information
at the point when dictionary content is not what we expect it to be.

and gap locks

  than with InnoDB plugin
  
  Fix: os0file.h in XtraDB had OS_AIO_N_PENDING_IOS_PER_THREAD 256
  when on InnoDB it is OS_AIO_N_PENDING_IOS_PER_THREAD 32. Changed
  XtraDB also to use 32.

  
  Analysis: Based on crashed the buffer pool instance identifier is
  not correct on block to be freed. Add LRU list mutex holding
  on functions calling free and add additional safety checks.

That particular part of slave connect to master was missing code to handle
retry in case of network errors. The same problem is present in MySQL 5.5, but
fixed in MySQL 5.6.

Fixed with this patch, by adding the code (mostly identical to MySQL 5.6), and
also adding a test case.

I checked other queries done towards master during slave connect, and they now
all seem to handle reconnect in case of network failures.

Fix an error case where success was returned instead of error.

use ascii 'x' not utf8 '×' for hex numbers

Merged WebScaleSQL fix:
https://github.com/webscalesql/webscalesql-5.6/commit/bce9eddc1da87beab17c60d7eb7379841a3d45af

- When range optimizer cannot the lookup value into [VAR]CHAR(n) column,
  it should produce:
  = "Impossible range" for equality
  = "no range" for non-equalities.

"have_warnings" was set to an uninialized value when converting
a negative number to datetime.

MDEV-6099 Bad results for DATE_ADD(.., INTERVAL 2000000000000000000.0 SECOND)
MDEV-6097 Inconsistent results for CAST(int,decimal,double AS DATETIME)
MDEV-6100 No warning on CAST(9000000 AS TIME)

We have to run the derived table prepare before the unique table check to mark the derived table (in this case the unique table check can turn that table to materialized one).

use -ggdb3 if supported

  Bug #18167356: EXPLAIN W/ EXISTS(SELECT* UNION SELECT*)
                 WHERE ONE OF SELECT* IS DISTINCT FAILS.

the bugfix itself was not merged - MariaDB doesn't have this bug.