Related:
- https://jira.mariadb.org/browse/MDEV-19780
- https://jira.mariadb.org/browse/MDEV-21944

Make package have sensible control file relations to mysql-8.0.

Also some cleanup:
- Remove obsolete versioned control relationships. When the package
  name already has a version older than current package, the extra
  version is obsolete.
- Remove obsolete postinst script that was empty
- Remove priority "extra" which is deprecated, use "optional" that
  applies for the whole source package instead.

The current debian/control file and other packaging of 10.5 targets the
latest Debian unstable. In autobake-deb.sh there are automatic build
adaptations for older Debian/Ubuntu releases.

Some adaptations were for Debian versions prior to Jessie and Ubuntu
versions prior to Trusty. Those distro releases are no longer supported
anyway, so these should be cleaned away now in the 10.5 release cycle.

Summary:
- Debian Jessie has libcrack2 release 2.9.2-1, no need to have adaptations
  for any older environments
- Debian Jessie has libpcre3-dev release 2:8.35-3.3, no need to consider
  older versions
- Systemd has been available since Debian Jessie, no need to consider
  that a Debian/Ubuntu environment would not have it available
  adaptations for environments for anything older

Regression after bfdd30d3. Initialize addition TABLE_LIST members which
are used by subsequent close_cached_tables() call.

It isn't an "option" anymore.

Make it static, coding style cleanup, declare consistently with all
callers (same ifdefs).

- Ignore system-invisible fields (as well as for setting default value);
- Handle rename of system time and period fields.

libmariadb revision updated.

This bug was introduced by MDEV-15528
commit a35b4ae8.

In the case that I analyzed, we failed to apply
an EXTENDED,INSERT_REUSE_REDUNDANT redo log record whose
preceding record points to unallocated area after PAGE_HEAP_TOP.

Had we properly written the FREE_PAGE record for the page,
recovery would have processed it, because during the checkpoint,
the log had been completely written past the LSN of the missed write.

fseg_free_page_low(): Always invoke mtr_t::free().
The other call is in fsp_free_page().

Let auto repair table and truncate table routines flush TABLE_SHARE
directly.

Part of MDEV-17882 - Cleanup refresh version

TDC_RT_REMOVE_ALL -> tdc_remove_table(). Some occurrences replaced with
TDC_element::flush() (whenver TABLE_SHARE is available).

TDC_RT_REMOVE_NOT_OWN[_KEEP_SHARE] -> TDC_element::flush(). These modes
assume that current thread owns TABLE_SHARE reference, which means we can
avoid hash lookup and flush unused TABLE instances directly.

TDC_RT_REMOVE_UNUSED -> TDC_element::flush_unused(). Only [ab]used by
mysql_admin_table() currently. Should be removed eventually.

Part of MDEV-17882 - Cleanup refresh version

As tc_purge() never marks share flushed, let tdc_remove_table() do it
directly.

Part of MDEV-17882 - Cleanup refresh version

Aim of this patch is to remove tdc_remove_table(TDC_RT_REMOVE_UNUSED),
which was mistakenly introduced by 055a3334.

InnoDB allows only one open TABLE instance while performing table
truncation. To fulfill this requirement:
1. MDL_EXCLUSIVE has to be acquired to block concurrent threads from
   accessing given table
2. cached TABLE instances have to be flushed
3. another InnoDB requirement is such that TABLE_SHARE and remaining
   TABLE instance have to be invalidated and re-opened after truncation

This goes more or less inline with what regular TRUNCATE TABLE does.

Alternative solution would be handler::ha_delete_all_rows(), but InnoDB
doesn't implement it unfortunately.

Part of MDEV-17882 - Cleanup refresh version

Let DROP SERVER and ALTER SERVER perform fair affected tables flushing.
That is acquire MDL_EXCLUSIVE and do tdc_remove_table(TDC_RT_REMOVE_ALL).

Aim of this patch is elimination of another inconsistent use of
TDC_RT_REMOVE_UNUSED. It fixes (to some extent) a problem described in the
beginning of sql_server.cc, when close_cached_connection_tables()
interferes with concurrent transaction.

A better fix should probably introduce proper MDL locks for server
objects?

Part of MDEV-17882 - Cleanup refresh version

Removed redundant tdc_remove_table(TDC_RT_REMOVE_ALL). Share was marked
flushed by preceding wait_while_table_is_used() and eventually flushed by
close_all_tables_for_name().

Part of MDEV-17882 - Cleanup refresh version

close_all_tables_for_name() is always preceded by
wait_while_table_is_used(), which makes tdc_remove_table() redundant.
The only (now fixed) exception was close_cached_tables().

Part of MDEV-17882 - Cleanup refresh version

Rather than flushing caches with tdc_remove_table(TDC_RT_REMOVE_UNUSED)
flush them with extra(HA_EXTRA_FLUSH) instead. This goes inline with
regular FTWRL.

Part of MDEV-17882 - Cleanup refresh version

The template parameter mtr_t::OPT refers to optional, not optimized.
Also the default parameter mtr_t::NORMAL refers to optimized writes.
The name MAYBE_NOP would be more descriptive, conveying the idea
that a write to a durable page might not actually have any effect.

mtr_t::log_write(): Fix an off-by-one error.

MDEV-18851: multiple sized large page support (linux)

MDEV-22113 SIGSEGV, ASAN use-after-poison, Assertion `next_insert_id == 0' in handler::ha_external_lock

if the lookup_handler is allocated on the THD's memroot, it may
not live long enough to be deleted in handler::ha_external_lock()

Prevent errors like on FreeBSD

[ 56%] Linking CXX shared module ha_test_sql_discovery.so
cd /usr/home/dan/build-mariadb-server-10.5/storage/test_sql_discovery && /usr/local/bin/cmake -E cmake_link_script CMakeFiles/test_sql_discovery.dir/link.txt --verbose=1
/usr/bin/c++ -fPIC  -Wl,-z,relro,-z,now -fstack-protector --param=ssp-buffer-size=4 -O2 -g -DNDEBUG -D_FORTIFY_SOURCE=2 -DDBUG_OFF  -shared  -o ha_test_sql_discovery.so CMakeFiles/test_sql_discovery.dir/test_sql_discovery.cc.o -lpthread ../../libservices/libmysqlservices.a -lmysqld -lpthread
/usr/bin/ld: error: unable to find library -lmysqld

Also tested on OpenIndiana successfully.

Closes #1480

Ubuntu Bionic 18.04 LTS will be around until 2023 while Xenial is only to
2021. Thus Bionic is much more suitable as the Travis-CI default build
environment for the 10.5 branch.

For now, still keep one Xenial build to ensure backwards compatibility.

Disable main.udf test until MDEV-21976 is addressed.

Number of jobs dropped from 23 -> 17 and build time from 8-10 hours to
3-4 hours.

Drop GCC 6 and Clang 6 from build dependencies and version 6 is dropped
from the jobs matrix.

Also ignore arm64 and ppc64le on Bionic builds since they sporadically
fail.

innodb_buffer_pool_evict_uncompressed(): Remove the mutex acquisition
that was inadvertently added in 1a6f708e.

In MDEV-12353, the calls to mtr_t::memo_modify_page()
were accidentally removed along with
mlog_open_and_write_index() and its callers.

Let us resurrect the function to enable better debug checks.

mtr_t::flag_modified(): Renamed from mtr_t::set_modified()
and made private.

mtr_t::set_modified(): Take const buf_block_t& as a parameter.

In several mtr_t member functions, replace const buf_page_t&
parameters with const buf_block_t&, so that we can pass the
parameter to set_modified().

mtr_t::modify(): Add a MTR_MEMO_MODIFY entry for a block that
is guaranteed to be modified in the mini-transaction.

page_zip_clear_rec(): Explicitly initialize len
in non-debug builds to avoid a warning about possibly
invalid memset() length.

copy_keys_from_share(): Use reinterpret_cast instead of
manipulating a reference to a type-punned pointer.

This cleans up after the cleanup
commit 0515577d.

In commit a5584b13
some scrubbing-related status variables were removed along with
the background scrubbing code.
The status variable INNODB_ENCRYPTION_NUM_KEY_REQUESTS
was inadvertently removed as part of that.

innodb_status_variables[]: Restore "encryption_num_key_requests".

We introduce the test innodb.innodb_status_variables
in order to catch similar regressions in the future.

Because InnoDB is not freeing undo pages to the normal
free-page management, old undo log pages can be reused. Due to that,
it is possible (but unlikely) that the fields TRX_UNDO_NEEDS_PURGE
and TRX_UNDO_LOG_START relative to the free offset that is stored at
TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_START already have the correct value.
Hence, we must pass the mtr_t::OPT template parameter to silence the
debug assertion.

Other writes in trx_undo_header_create() that are using the default
template parameter seem to be correct (the data fields should be
guaranteed to change even in the event of reusing pages).