non-functional cleanup, clarifying CONVERT_IF_BIGGER_TO_BLOB
MDEV-3987 uninitialized read in Item_cond::fix_fields leads to crash: select .. where .. in ( select ... )

change Item_func_group_concat to use max_length according to the expected semantics
MDEV-3883 Show global status not in order
MDEV-3985 crash: uninstall soname 'a'
MDEV-3846 REFRESH_CHECKPOINT and REFRESH_TABLE_STATS tokens share the same value
Fix for MDEV-4009: main.delayed sporadically fails with "query 'REPLACE DELAYED t1 VALUES (5)' failed: 1317: Query execution was interrupted"
- Fixed broadcast without a proper mutex
- Don't break existing locks if we are just testing if we can get the lock
Fixed some race conditons and bugs related to killed queries
KILL now breaks locks inside InnoDB
Fixed possible deadlock when running INNODB STATUS
Added ha_kill_query() and kill_query() to send kill signal to all storage engines
Added reset_killed() to ensure we don't reset killed state while awake() is getting called
Fixed MDEV-4013: Password length in replication setup
Give error for wrong parameters to CHANGE MASTER
Extend MASTER_PASSWORD and MASTER_HOST lengths
Fixed problem with failing mysql_upgrade when proc table was not correct.
Moved out creation of performance schema tables from mysql_system_tables.sql as
the performance_tables creation scripts needs a working mysql.proc to work.
Fixed crashing bug in GROUP_CONCAT with ROLLUP
Fixed MDEV-4002: Server crash or valgrind errors in Item_func_group_concat::setup and Item_func_group_concat::add
Buildbot fixes and cleanups:
- Added --verbose to BUILD scripts to get make to write out compile commands.
- Detect if AM_EXTRA_MAKEFLAGS=VERBOSE=1 was used with build scripts.
- Don't write warnings about replication variables when doing bootstrap.
- Fixed that mysql_cond_wait() and mysql_cond_timedwait() will report original source file in case of errors.
- Ignore some compiler warnings