Adding a global/session var `redirect_url' of string type. The initial
value is empty. Can be supplied in mysqld with --redirect-url or set
in --init-connect. A valid redirect_url should be of the format

{mysql,mariadb}://host[:port]

where <host> is an arbitrary string not containing colons, and <port>
is a number between 0 and 65535 inclusive.

The variable will be used by the server to notify clients that they
should connect to another server, specified by the value of the
variable, if not empty.

The notification is done by the inclusion of the variable in
session_track_system_variable.

Merge sys_var_charptr with sys_var_charptr_base, as well as merge
Sys_var_session_lexstring into Sys_var_lexstring. Also refactored
update methods of sys_var_charptr accordingly.

Because the class is more generic, session_update() calls
sys_var_charptr::session_update() which does not assume a buffer field
associated with THD, but instead call strdup/free, we get rid of
THD::default_master_connection_buff accordingly. This also makes THD
smaller by ~192 bytes, and there can be many thousands of concurrent
THDs.

New Feature:
============
This patch extends the START SLAVE UNTIL command with options
SQL_BEFORE_GTIDS and SQL_AFTER_GTIDS to allow user control of
whether the replica stops before or after a provided GTID state. Its
syntax is:

START SLAVE UNTIL (SQL_BEFORE_GTIDS|SQL_AFTER_GTIDS)=”<gtid_list>”

When providing SQL_BEFORE_GTIDS=”<gtid_list>”, for each domain
specified in the gtid_list, the replica will execute transactions up
to the GTID found, and immediately stop processing events in that
domain (without executing the transaction of the specified GTID).
Once all domains have stopped, the replica will stop. Events
originating from domains that are not specified in the list are not
replicated.

START SLAVE UNTIL SQL_AFTER_GTIDS=”<gtid_list>” is an alias to the
default behavior of START SLAVE UNTIL master_gtid_pos=”<gtid_list>”.
That is, the replica will only execute transactions originating from
domain ids provided in the list, and will stop once all transactions
provided in the UNTIL list have all been executed.

Example:
=========
If a primary server has a binary log consisting of the following GTIDs:

0-1-1
1-1-1
0-1-2
1-1-2
0-1-3
1-1-3

If a fresh replica (i.e. one with an empty GTID position,
@@gtid_slave_pos='') is started with SQL_BEFORE_GTIDS, i.e.

START SLAVE UNTIL SQL_BEFORE_GTIDS=”1-1-2”

The resulting gtid_slave_pos of the replica will be “1-1-1”.
This is because the replica will execute only events from domain 1
until it sees the transaction with sequence number 2, and
immediately stop without executing it.

If the replica is started with SQL_AFTER_GTIDS, i.e.

START SLAVE UNTIL SQL_AFTER_GTIDS=”1-1-2”

then the resulting gtid_slave_pos of the replica will be “1-1-2”.
This is because it will only execute events from domain 1 until it
has executed the provided GTID.

Reviewed By:
============
Kristian Nielson <knielsen@knielsen-hq.org>

utf8mb4_general_ci has been outdated for a while and contained loosely
standardized collations.

UCA-14.0.0 has a more defined collation with multiple benefit that new
users may not immediately consider, or may assume to be default.

By defining default collation for utf8mb4 to be uc1400_ai_ci newly
created tables will have a modern standard collation.

Before starting to go over the format string, prepare the current time
zone information incase '%z' or '%Z' is encountered.
This information can be obtained as given below:

A) If timezone is not set ( meaning we are working with system timezone):
Get the MYSQL_TIME representation for current time and GMT time using
current thread variable for timezone and timezone variable for UTC
respectively. This MYSQL_TIME variable will be used to calculate time
difference. Also convert current time in second to tm structure to
get system timezone information.

B) If timezone is set as offset:
Get timezone information using current timezone information and store
in appropriate variable.

C) If timezone is set as some place (example: Europe/Berlin)
Get timezone information by searching the timezone. During internal
timezone search, information like timeoffset from UTC and abbrevation
is stored in another relevant structure. Hence use the same information.

Refactor CPackWixConfig.cmake so that it complains about unknown CPack
components.

This would prevent missing components,or discrepancy between MSI and ZIP
content, whenever new components are added or renamed.

Also, remove some old stuff, and use macros add_component_group() and
add_component() to reduce the verbosity.

Move files to the mariadb-test package that are created during the build
but were not included in the package yet.

remove old deprecation helpers that were not used anywhere.

create new deprecation helpers and enforce their usage

this also removes inconsistencies in reporting deprecation:
sometimes it was ER_WARN_DEPRECATED_SYNTAX (1287),
sometimes ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT (1681),
sometimes a warning, sometimes a note.

it should always be
* ER_WARN_DEPRECATED_SYNTAX
* a warning (because it's something actionable, not purely informational)

after fb175a1b

it was introduced in ff8651c4 to suppress deprecated
warnings for CALL under the flawed logic that "It's doesn't
make sense to print out deprecated syntax warnings when the
routine is being executed because this kind of warning only
matters when the routine is being created".

Which is incorrect, a feature might become deprecated after
the routine was created and a user has to know that to be able
to update the procedure before it stops working when a
deprecated feature is removed.

mark non-default values of old_mode as deprecated.
print a warning when they're set from the command line and in SQL.

In particular:

* @@debug
  deprecated since 5.5.37
* sr_YU locale
  deprecated since 10.0.11
* "engine_condition_pushdown" in the @@optimizer_switch
  deprecated since 10.1.1
* @@date_format, @@datetime_format, @@time_format, @@max_tmp_tables
  deprecated since  10.1.2
* @@wsrep_causal_reads
  deprecated since 10.1.3
* "parser" in mroonga table comment
  deprecated since 10.2.11

KDF(key_str, salt [, {info | iterations} [, kdf_name [, width ]]])

kdf_name is "hkdf" or "pbkdf2_hmac" (default).

width (in bits) can be any number divisible by 8,
by default it's taken from @@block_encryption_mode

iterations must be positive, and is 1000 by default

OpenSSL 1.0 doesn't support HKDF, so it'll return NULL.
This OpenSSL version is still used in SLES 12 and CentOS 7

like ErrConvString, but puts the string in 'single quotes'

followup for 7ba9c7fb

* don't introduce random four-space-gaps into the middle of description
  (meaning, nicely aligned wrapped string in the code gets ugly
  in the rpm)
* remove obsolete comment
* MariaDB-connect-engine is a required package for MariaDB-connect-engine-jdbc
  not "recommended"
* don't recommend both mariadb-java-client and mysql-connector-java
* in fact, don't recommend anything, it works badly for old rpm < 4.13,
  installs something that user may not want, and install redundand deps.
  Let's rethink how to do it meaningfully. And not break tests.

followup for 7ba9c7fb

Not ready yet, it fails its own test suite

This reverts commit 485c9b1f

first seen in daca468c

Commit 738d4604 changed component name
from "backup" to "Backup". Use the new name now.

Fix the Cache_flip_event_log constructor.

- optimize atomic store64/load64 implementation.
- allow CRC32 optimization. Do not allow pmull yet, as this fails like in
  https://stackoverflow.com/questions/54048837/how-to-perform-polynomial-multiplication-using-arm64

- Removing two copies of the drop_routine.
  Adding a shared and much simplified version.

- Removing LEX metods:
      bool stmt_drop_function(const DDL_options_st &options,
                              const Lex_ident_sys_st &db,
                              const Lex_ident_sys_st &name);

      bool stmt_drop_function(const DDL_options_st &options,
                              const Lex_ident_sys_st &name);

      bool stmt_drop_procedure(const DDL_options_st &options,
                               sp_name *name);

  The code inside the methods was very similar.
  Adding one method instead:

      bool stmt_drop_routine(const Sp_handler *sph,
                          const DDL_options_st &options,
                          const Lex_ident_sys_st &db,
                          const Lex_ident_sys_st &name);

- Adding a new virtual method Sp_handler:sqlcom_drop().
  It helped to unify the code inside the new stmt_drop_routine().

Resolving the shift/reduce conflict conflict in:

GRANT ..  ON /*ambiguity*/ FUNCTION f1 TO foo@localhost;
GRANT ... ON /*ambiguity*/ [TABLE] function TO foo@localhost;

and in

REVOKE ..  ON /*ambiguity*/ FUNCTION f1 TO foo@localhost;
REVOKE ... ON /*ambiguity*/ [TABLE] function TO foo@localhost;

using a new %prec directive.