MDEV-405: Server crashes in test_if_skip_sort_order on EXPLAIN with GROUP BY and HAVING in EXISTS subquery
- Testcase

- Don't do early cleanup of uncorrelated subqueries if we're running an EXPLAIN.

        the fill_help_table-5.5.sql file was copied into mariadb.

per-file comments:
  scripts/fill_help_tables.sql
        MDEV-471 update help tables.

force -fno-strict-aliasing for oqgraph

The problem was that was_null and null_value variables was reset in each reexecution of IN subquery, but engine rerun only for non-constant subqueries.

Fixed checking constant in Item_equal sort.
Fix constant reporting in Item_subselect.

Various places in the server replication code was incorrectly quoting
strings, which could lead to incorrect SQL on the slave/mysqlbinlog.

fix mysys/waiting_threads.c to compile w/o performance schema
include clients. scripts and manpages in -DWITHOUT_SERVER

only add cmake as a build dependency for distributions, where cmake is recent enough

Item::get_date() should return 1 unless the value is a valid date.

two tests still fail:
  main.innodb_icp and main.range_vs_index_merge_innodb
  call records_in_range() with both range ends being open
  (which triggers an assert)

increase xtradb verson from 13.0 to 13.01

The fix backports from MWL#182: Explain running statements the logic that
saves the original JOIN_TAB array of a query plan after optimization. This
array is later used during EXPLAIN to iterate over the original JOIN plan
nodes in the cases when this plan could be changed by early subquery
execution during the optimization phase of the outer query.

The crash happend when combining query cache, prepared statements and using a read only cursor.

sql/sql_cache.cc:
  Fixed unlikely error when one adjust query cache size in middle of operation
sql/sql_cursor.cc:
  Disable query cache when using cursors. This fixed lp:1039277
tests/mysql_client_test.c:
  Test case for lp:1039277

sql/handler.cc:
  SHOW INNODB STATUS sometimes returns 0 even if it has generated an error.
  This code is here to catch it until InnoDB some day is fixed.
storage/innobase/handler/ha_innodb.cc:
  Catch at least one of the possible errors from SHOW INNODB STATUS to provide a correct return code.
storage/xtradb/handler/ha_innodb.cc:
  Catch at least one of the possible errors from SHOW INNODB STATUS to provide a correct return code.
support-files/my-huge.cnf.sh:
  Fixed typo