MTR drops the datadir in the event of a test failure. In case mysqld
is running as a Galera node and a failure occurs while the SST is in
progress, the rsync pid file gets removed as part of the cleanup and
wsrep_sst_rsync, which relies on this file, fails to kill the rsync.
Fixed by using the cached $RSYNC_REAL_PID to kill rsync daemon.

Item_direct_view_ref maintains its own item_const() method so should use it when asked of temporary table field to be in sync with it.

Non-select-like queries has no correct JOIN structure connected to top-most SELECT_LEX (and should not).

MDEV-7930 Assertion `table_share->tmp_table != NO_TMP_TABLE || m_lock_type != 2' failed in  handler::ha_index_read_map

In optimizing aggregate function do not try to touch tables from outer
query.

            ha_partition::init_record_priority_queue()

Cherry-pick rev.6b0ee0c795499cee7f9deb649fb010801e0be4c2 from mysql-5.6.

Bug #18305270  BACKPORT BUG#18694052 FIX
               FOR ASSERTION `!M_ORDERED_REC_BUFFER'
               FAILED TO 5.6

PROBLEM
-------
Missed to remove record priority queue if
init_index failed for a partition which
was causing the crash.

FIX
---
Remove priority queue if init_index fails
for partition.

In buffer pool read hit rate calculation can lead rate that is
less than zero.

Analysis: Current implementation will write and read at least one block
(sort_buffer_size bytes) from disk / index even if that block does not
contain any records.

Fix: Avoid writing / reading empty blocks to temporary files (disk).

Since MariaDB packages have absolute paths, they are marked as not relocatable
by setting CPACK_RPM_PACKAGE_RELOCATABLE. According to logics of recent CPackRPM
it is not enough: one needs to set CPACK_PACKAGE_RELOCATABLE additionally.

mysql_secure_installation used incorrect path while looking up for "mysql"
client tool: $basedir/$basedir/bin instead of $basedir/bin.

This patch adapts "my_print_defaults" lookup algorithm for "mysql" client tool.

MDEV-8358 ALTER TABLE .. ADD PRIMARY KEY IF NOT EXISTS -> ERROR 1068 (42000): Multiple primary key defined
        Checks for multiple primary keys added.

Author: Marc Alff <marc.alff@oracle.com>
Date:   Thu Jul 30 11:17:50 2015 +0200

    Bug#21528683 SLOWDOWN CAUSED BY MEMSET IN SQL_DIGEST_STORAGE.RESET()

use CHECK_C_SOURCE_COMPILES for atomic tests if cross-compiling
(continue to use CHECK_C_SOURCE_RUNS otherwise)

Assertion `inited==INDEX' failed in int handler::ha_index_first(uchar*)

The crash was because errors from init_read_record_idx() was not taken care of.

don't abort with "XtraDB not supported" if XtraDB was disabled
in this build.

add a run-time check for jemalloc >= 2.3

don't forget to re-examine the current element when updating a HASH

strip endspaces from the role name in the parser
because they'll be lost anyway when the name is stored
in the mysql.user.user column (of type CHAR)

allow SET PASSWORD from  bootstrap and init-file

  modified:   storage/connect/tabodbc.cpp

new features:
set event_scheduler=ON|OFF will now try to init event scheduler
if it's not enabled
set event_scheduler=default will try to enable it based on
the value of the event_scheduler when mysqld was started

reload grant tables.

cherry-picked 7454f1c5 from 10.1