Also fixed that all unused variables are using the same variable comment.
The warning will be tested with the next commit that deprecates the
variable alter_algorithm.

MDEV-32188 make TIMESTAMP use whole 32-bit unsigned range

This was done by changing DTVAL to use longlong to internally store
the date/timestamp instead of an int.

I had to preserve the old binary representation used for dates in
TABLE_TYPE=BIN. One consequence is that TABLE_TYPE=BIN cannot support
the full date bit range.

MDEV-32188 make TIMESTAMP use whole 32-bit unsigned range

- Changed usage of timeval to my_timeval as the timeval parts on windows
  are 32-bit long, which causes some compiler issues on windows.

MDEV-32188 make TIMESTAMP use whole 32-bit unsigned range

This is done by changing my_time_t from long to unsigned long.
The effect of this is that on windows compling old clients may
get warnings of if they compare my_time_t with as signed variable.

Other things
- Removed my_time_t from include/*.pp files as it is different on windows
  and linux.
- Changed do_abi_check.cmake to first print abi_check and then the
  conflicting file (this makes it easier to find the cause of the error).

This patch extends the timestamp from
2038-01-19 03:14:07.999999 to 2106-02-07 06:28:15.999999
for 64 bit hardware and OS where 'long' is 64 bits.
This is true for 64 bit Linux but not for Windows.

This is done by treating the 32 bit stored int as unsigned instead of
signed.  This is safe as MariaDB has never accepted dates before the epoch
(1970).
The benefit of this approach that for normal timestamp the storage is
compatible with earlier version.

However for tables using system versioning we before stored a
timestamp with the year 2038 as the 'max timestamp', which is used to
detect current values.  This patch stores the new 2106 year max value
as the max timestamp. This means that old tables using system
versioning needs to be updated with mariadb-upgrade when moving them
to 11.4. That will be done in a separate commit.

- Slave_IO thread time is now reset between reading events. Before
  this commit Slave_IO always showed "Waiting for master to send
  event" and the time was from SLAVE START. Now it shows time since
  reading last event.

This is to make it easier to understand why master_pos_wait() fails in mtr.

Fixed that no tables from 'mysql' schema are included in userstat.
A beneif of this is that the server is not reading statistics tables
if mysql.proc or other tables in mysql is accessed.

Other changes:
- Do not collect index statistics for system tables like index_stats
  table_stats, performance_schema, information_schema etc as the user
  has no control of these and the generate noise in the statistics.

what is done in the plugin - stays in the plugin

and adjust the copyright year

This is to update the plugin to be compatible with Percona's
query_response_time plugin, with some additions.
Some of the tests are taken from Percona server.

- Added plugins QUERY_RESPONSE_TIME_READ, QUERY_RESPONSE_TIME_WRITE and
  QUERY_RESPONSE_TIME_READ_WRITE.
- Added option query_response_time_session_stats, with possible values
  GLOBAL, ON or OFF, to the query_response_time plugin.

Notes:
- All modules are dependent on QUERY_RESPONSE_READ_TIME. This must always
  be enabled if any of the other modules are used.
  This will be auto-enabled in the near future.
- Accounting are done per statement. Stored functions are regarded
  as part of the original statement.
- For stored procedures the accounting are done per statement executed
  in the stored procedure. CALL will not be accounted because of this.
- FLUSH commands will not be accounted for. This is to ensure that
  FLUSH QUERY_RESPONSE_TIME is not part of the statistics.
  (This helps when testing with mtr and otherwise).
- FLUSH QUERY_RESPONSE_TIME_READ and FLUSH QUERY_RESPONSE_TIME_READ
  only resets the corresponding status.
- FLUSH QUERY_RESPONSE_TIME and FLUSH QUERY_RESPONSE_TIME_READ_WRITE or
  changing the value of query_response_time_range_base followed by
  any FLUSH of QUERY_RESPOSNSE_TIME resets all status.

Various help message improvements:
* MySQL->MariaDB, mysqld->mariadbd, "mysqld daemon" -> "mariadbd process"
* typos
* don't specify defaults directly in the help message
* don't say that an option is deprecated, mark is as such
* missing spaces in the middle of the text
etc

it was a no-op, plugin variables don't have dashes

* use new deprecated printer for all deprecated server options
* restore alphabetic option sorting order
* move deprecated printer from mysqld.cc to my_getopt.c
* in --help print deprecation message at the end of the option help
* move 'ALL' help text where it belongs - to other SET options, and
  with a correct indentation.
* consistently end all or none command-line option help strings
  with a dot - my_print_help() needs that.
  It's about 50/50 now, so let's do none, less line wraps in --help
* remove trailing spaces from command-line option help strings

Currently there are mechanism to mark a system variable as
deprecated, but they are only used to print warning messages
when a deprecated variable is set.

Leverage the existing mechanisms in order to make the
deprecation information available at the --help output of mysqld by:

* Moving the deprecation information (i.e `deprecation_substitute`
  attribute) from the `sys_var` class into the `my_option` struct.
  As every `sys_var` contains its own `my_option` struct, the access
  to the deprecation information remains available to `sys_var`
  objects. `my_getotp` functions, which works directly with
  `my_option` structs, gain access to this information while building
  the --help output.

* For plugin variables, leverages the `PLUGIN_VAR_DEPRECATED` flag
  and set the `deprecation_substitute` attribute  accordingly when
  building the `my_option` objects.

* Change the `option_cmp` function to use the `deprecation_substitute`
  attribute instead of the name when sorting the options. This way
  deprecated options and the substitutes will be grouped together.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer
Amazon Web Services, Inc.

The problem seems to be fixed earlier in the MDEV-25829 stage branch.
Removing the --disable_view_protocol command.

A user variable and a literal with different collation
produce an illegal mix of collation error.
Rewriting the script to avoid such arguments.

Step#3 The main patch

Step#2 - Adding a new collation derivation level for CAST and CONVERT.

Now character string cast functions:
  - CAST(string_expr AS CHAR)
  - CONVERT(expr USING charset_name)

have a new collation derivation level between:

  - string literals
  - utf8 metadata functions, e.g. user() and database()

Before the change these cast functions had collation derivation equal
to table columns, which caused more illegal mix of collation conflicts.

Note, binary string cast functions:
  - BINARY(expr)
  - CAST(string_expr AS BINARY)
  - CONVERT(expr USING binary)
did not change their collation derivation, to preserve the behaviour of
queries like these:
SELECT database()=BINARY'test';
SELECT user()=CAST('root' AS BINARY);
SELECT current_role()=CONVERT('role' USING binary);

Derivation levels after the change look as follows:

  DERIVATION_IGNORABLE= 7, // Explicit NULL

  DERIVATION_NUMERIC= 6,   // Numbers in string context,
                           // Numeric user variables
                           // CAST(numeric_expr AS CHAR)

  DERIVATION_COERCIBLE= 5, // Literals, string user variables

  DERIVATION_CAST= 4,      // CAST(string_expr AS CHAR),
                           // CONVERT(string_expr USING cs)

  DERIVATION_SYSCONST= 3,  // utf8 metadata functions, e.g. user(), database()
  DERIVATION_IMPLICIT= 2,  // Table columns, SP variables, BINARY(expr)
  DERIVATION_NONE= 1,      // A mix (e.g. CONCAT) of two differrent collations
  DERIVATION_EXPLICIT= 0   // An explicit COLLATE clause

Step#1 - Changing collation derivation for string user variables
from IMPLICIT to COERCIBLE.

Retionale:

Without this preparatory change, switching the default collation for
Unicode character sets from xxx_general_ci to uca1400_ai_ci would cause
"Illegal mix of collations" errors in scenarios comparing a column with
a non-default collation to a string user variable

This is especially important for queries to INFORMATION_SCHEMA tables,
whose columns use utf8mb3_general_ci.

See the description of MDEV-25829 for more details and SQL script examples.

MDEV-33672 (10.6) added checks/tests for malformed events which end
before the flags describe (which would lead to reading of un-owned
memory). MDEV-7850 (11.5) extended all GTID events with a thread id
at the end of the event. This GTID event extension invalidates the
tests added in MDEV-33672 because the thread id is appended after the
event (and thereby the event isn't cut short).

This patch fixes these MDEV-33672 tests by not writing the GTID
thread id when writing the Gtid events just for these tests. This
preserves tests for backwards compatibility, rather than getting rid
of the tests altogether.

trx_undo_mem_create_at_db_start(): Invoke recv_sys_t::recover()
instead of buf_page_get_gen(), so that all undo log pages will be
recovered correctly. Failure to do this could prevent InnoDB from
starting up due to "Data structure corruption", or it could
potentially lead to a situation where InnoDB starts up but some
transactions were recovered incorrectly.

recv_sys_t::recover(): Only acquire a buffer-fix on the pages,
not a shared latch. This is adequate protection, because this function
is only being invoked during early startup when no "users" are modifying
buffer pool pages. The only writes are due to server bootstrap
(the data files being created) or crash recovery (changes from
ib_logfile0 being applied).

buf_page_get_gen(): Assert that the function is not invoked while crash
recovery is in progress, and that the special mode BUF_GET_RECOVER is
only invoked during crash recovery or server bootstrap.

All this should really have been part of
commit 850d6173 (MDEV-32042).

MDEV-33729 UBSAN negation of -X cannot be represented in type 'long long int'; cast to an unsigned type to negate this value to itself in my_strntoll_mb2_or_mb4

The problem was introduced by MDEV-30879.
The function my_strntoll_8bit() was correctly changed by MDEV-30879.
The function my_strntoll_mb2_or_mb4() was not.

Applying the missing change to my_strntoll_mb2_or_mb4().

		in buf_dblwr_t::init_or_load_pages()

- InnoDB fails to set the TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED
flag in transaction system header page while recreating
the undo log tablespaces

buf_dblwr_t::init_or_load_pages(): Tries to reset the
space id and try to write into doublewrite buffer even
when read_only mode is enabled.

In srv_all_undo_tablespaces_open(), InnoDB should try to
open the extra unused undo tablespaces instead of trying to
creating it.