Simplifying definitions on Sys_var_charptr*:

- Removing sys_var::is_os_charset
- Adding a new class Sys_var_charptr_fscs, to handle system
  variables with character_set_filesystem.

Move function ut_crc32_swap_byteorder to a non-x86 #ifdef area.

As its only used in BIGENDIAN, use #ifdefs around
ut_crc32_swap_byteorder.

Travis CI and Debian both include s390x in builds/test, which is big endian.

Fixes commit: 1312b4eb

log_write_buf(): Remove the unused variable write_header.
The dependent code was removed in
commit 0c2365c4.
That was dead or unnecessary code at least ever since
commit 9ef2d29f
removed the support for innodb_log_files_in_group>1.

mi_records_in_range(): Because HA_POS_ERROR cannot be accurately
represented in double (it will be off by one), add an explicit
cast to silence the warning.

log_t::has_encryption_key_rotation(): checks whether
key rotation is supported.

In a subsequent redo log format version, this key rotation
may be broken again.

Write log header just ones when file is created, instead of
writing to it on every log file wrap around.

log_t::file::write_header_durable(): this one writes to log header

log_write_buf(): this one stops writing to log header

move statistics modification into one place

restore check for client charset_info == NULL, which was previously
removed in MDEV-8844

that by a (un)lucky coincidence did not prevent 8fd654ce
from working properly

when selecting from perfschema, filter out statements
used by the test istself in wait_condition.inc, because they,
by design, can be repeated unpredictable number of times.

By default, when redo log is being written for modifying a persistent
data page, the data page must actually be changed. If the write can
sometimes be optimized away, then the template parameter w=mtr_t::OPT
should be passed in order to silence the debug assertion failure.

InnoDB undo log pages can be reused without properly freeing or
initializing them in between. In particular, the undo log header
page field TRX_UNDO_TRX_NO could have been part of an undo log
record page, and those bytes could accidentally have the desired
value when the page is reused as an undo log header page of
another transaction.

Because the function trx_undo_set_state_at_finish() always changes
the TRX_UNDO_STATE of the page, and because recovery is only reading
TRX_UNDO_TRX_NO for pages that either have the correct TRX_UNDO_STATE
or, in trx_rseg_array_init(), are attached to the TRX_SYS page, the
garbage values in TRX_UNDO_TRX_NO do not seem to cause a problem.

This assertion failure affects debug builds only.

Force correct PCRE2 linking in the official binaries.
System pcre2 in RPM/DEB, bundled in bintars.

fix build requirements for debian

strip all client binaries (that is, not mysqld) in bintars

in mysql_release builds only build embedded for rpm and deb
but not for bintar

e.g.
- dont -> don't
- occurence -> occurrence
- succesfully -> successfully
- easyly -> easily

Also remove trailing space in selected files.

These changes span:
- server core
- Connect and Innobase storage engine code
- OQgraph, Sphinx and TokuDB storage engines

Related to MDEV-21769.

Instrument new synchronization primitive with thd_wait_begin/end
to inform threadpool about waits.

This considerably improve performance on write benchmarks
(e.g sysbench update_index) with generic threadpool, of course the cost is
possibility of many newly created threads.

Addon fields will be packed if the length of addon fields is greater
than max_length_for_sort_data.

Fixed XA-ROLLBACK not to write into binlog when XA-prepare run
in sql_log_bin-OFF environment. (Two tests affected).

Part of
MDEV-742 - XA PREPAREd transaction survive disconnect/server restart

Lifted long standing limitation to the XA of rolling it back at the
transaction's
connection close even if the XA is prepared.

Prepared XA-transaction is made to sustain connection close or server
restart.
The patch consists of

    - binary logging extension to write prepared XA part of
      transaction signified with
      its XID in a new XA_prepare_log_event. The concusion part -
      with Commit or Rollback decision - is logged separately as
      Query_log_event.
      That is in the binlog the XA consists of two separate group of
      events.

      That makes the whole XA possibly interweaving in binlog with
      other XA:s or regular transaction but with no harm to
      replication and data consistency.

      Gtid_log_event receives two more flags to identify which of the
      two XA phases of the transaction it represents. With either flag
      set also XID info is added to the event.

      When binlog is ON on the server XID::formatID is
      constrained to 4 bytes.

    - engines are made aware of the server policy to keep up user
      prepared XA:s so they (Innodb, rocksdb) don't roll them back
      anymore at their disconnect methods.

    - slave applier is refined to cope with two phase logged XA:s
      including parallel modes of execution.

This patch does not address crash-safe logging of the new events which
is being addressed by MDEV-21469.

CORNER CASES: read-only, pure myisam, binlog-*, @@skip_log_bin, etc

Are addressed along the following policies.
1. The read-only at reconnect marks XID to fail for future
   completion with ER_XA_RBROLLBACK.

2. binlog-* filtered XA when it changes engine data is regarded as
   loggable even when nothing got cached for binlog.  An empty
   XA-prepare group is recorded. Consequent Commit-or-Rollback
   succeeds in the Engine(s) as well as recorded into binlog.

3. The same applies to the non-transactional engine XA.

4. @@skip_log_bin=OFF does not record anything at XA-prepare
   (obviously), but the completion event is recorded into binlog to
   admit inconsistency with slave.

The following actions are taken by the patch.

At XA-prepare:
   when empty binlog cache - don't do anything to binlog if RO,
   otherwise write empty XA_prepare (assert(binlog-filter case)).

At Disconnect:
   when Prepared && RO (=> no binlogging was done)
     set Xid_cache_element::error := ER_XA_RBROLLBACK
     *keep* XID in the cache, and rollback the transaction.

At XA-"complete":
   Discover the error, if any don't binlog the "complete",
   return the error to the user.

Kudos
-----
Alexey Botchkov took to drive this work initially.
Sergei Golubchik, Sergei Petrunja, Marko Mäkelä provided a number of
good recommendations.
Sergei Voitovich made a magnificent review and improvements to the code.
They all deserve a bunch of thanks for making this work done!

revert e74c1c9e to restore 2bbcf9a1

also remove redundant --connection commands

mariabackup tries to allocate a buffer of page_size*page_size/4 size.
for 64k page it means 1Gb, which doesn't work very well on 32-bit builders.

Skip the 64k page test on 32bit.

this fixes main.mysqld--defaults-file failure with --mem