The value of system variable use_stat_tables was always reset to 0 ('never') 
by mistake at the launch of the server.

two items didn't do that properly, one was exploitable, the other was not, but fixed anyway.

manually checked every change, reverted incorrect or stupid changes.

remove unused mtr option

sql/log.h:
  Fixed compiler warnings reported for gcc 2.7.1
storage/xtradb/handler/ha_innodb.cc:
  Remove not used variables

When appliying parent combinations to the overlay,
filter them through the %skip_combinations using the overlayed filename

Post-merge fixes for mismatches that only affect 5.5 (but not 5.3)

Following reasons caused mismatches:
  - different handling of invalid values;
  - different CAST results with fractional seconds;
  - microseconds support in MariaDB;
  - different algorithm of comparing temporal values;
  - differences in error and warning texts and codes;
  - different approach to truncating datetime values to time;
  - additional collations;
  - different record order for queries without ORDER BY;
  - MySQL bug#66034.
More details in MDEV-369 comments.

make CMakeLists.txt to detect if the installed boost can be compiled with the
installed compile and specified set of compiler options.

Background: even sufficiently new Boost cannot be compiled with the sufficiently old gcc
in the presence of -fno-rtti

add missing checks to configure.cmake
remove dead code and unused HAVE_xxx constants from the sources

Don't use ER(xxx) in THD::close_connection(), when current_thd is already reset to NULL.
Prefer ER_THD() or ER_DEFAULT() instead.

      mysql_rm_table_no_locks() function was modified.
      When we construct log record for the DROP TABLE, now we
      look if there's a comment before the first table name and
      add it to the record if so.
  
per-file comments:
  sql/sql_table.cc
  MDEV-340 Save replication comments for DROP TABLE.
        comment_length() function implemented to find comments in the query,
        call it in mysql_rm_table_no_locks() and use the result to form log record.
  mysql-test/suite/binlog/r/binlog_drop_if_exists.result
  MDEV-340 Save replication comments for DROP TABLE.
        test result updated.
  mysql-test/suite/binlog/t/binlog_drop_if_exists.test
  MDEV-340 Save replication comments for DROP TABLE.
        test case added.

Add the check for sys/utsname.h to configure.cmake

use correct macro for Microsoft compiler. It is _MSC_VER , not _MSV_VER

Following reasons caused mismatches:
  - different handling of invalid values;
  - different CAST results with fractional seconds;
  - microseconds support in MariaDB;
  - different algorithm of comparing temporal values;
  - differences in error and warning texts and codes;
  - different approach to truncating datetime values to time;
  - additional collations;
  - different record order for queries without ORDER BY;
  - MySQL bug#66034.
More details in MDEV-369 comments.

into a separate file stat_tables_par.test because the test cases
could not be run with embedded server.

Replaced bzero with memset.
Added missing --source include/have_debug_sync.inc into stat_tables.test.

  - Moved the definitions of the classes to store data from persistent
    statistical tables into statistics.h, leaving in other internal 
    data structures only references to the corresponding objects.
  - Defined class Column_statistics_collected derived from the class
    Column_statistics. This is a helper class to collect statistics
    on columns.
  - Moved references to read statistics to TABLE SHARE, leaving the
    the reference to the collected statistics in TABLE.
 - Added a new clone method for the class Field allowing to clone
    fields attached to table shares. It was was used to create 
    fields for min/max values in the memory of the table share.
A lso:
  - Added procedures to allocate memory for statistical data in
    the table share memory and in table memory.
Also: 
  - Added a test case demonstrating how ANALYZE could work in parallel
    to collect statistics on different indexes of the same table.
  - Added a test two demonstrate how two connections working 
    simultaneously could allocate memory for statistical data in the 
    table share memory.  
   

- Make Item_subselect::fix_fields() ignore UNCACHEABLE_EXPLAIN flag when deciding whether 
  the subquery item should be marked as constant.

Fix : use attribute %config(noreplace)  for /etc/my.cnf , instead of (automatically generated) %config

see https://mariadb.atlassian.net/browse/MDEV-11

- index_merge/intersection is unable to work on GIS indexes, because:
  1. index scans have no Rowid-Ordered-Retrieval property
  2. When one does an index-only read over a GIS index, they do not 
     get the index tuple, because index only contains bounding box of the geometry.
     This is why key_copy() call crashed.
This patch fixes #1, which makes the problem go away. Theoretically, it would 
be nice to check #2, too, but SE API semantics is not sufficiently precise to do it.

Now partition engine adds underlying tables to the QC and ask underlying tables engine permittion to cache the query and return result of the query.

Incorrect QC cleanup in case of table registration failure fixe.

Unified interface for myisammrg & partitioned engnes for QC.

MDEV-393. Remove --loose-pbxt=OFF/loose-skip-pbxt from bootstrapper calls to avoid "unknown parameter" warning