post-merge fixes:
* .gitignore
* don't put the keyword COMPONENT into ${COMP} anymore
* don't alias mytop, but do alias mysql_client_test
* don't symlink manpages, use troff aliasing technique instead
  (symlinked manpages break rpm and out-of-source bintar builds)
* move debian to use troff aliased manpages, fix typos in debian files,
  put aliases in the correct packages, add more aliases to match
  rpm/bintar packaging

in HEAP btree indexes, the address of a record in memory is part of the
key. So, when inserting many identical keys, the actual btree
shape is defined by how and where records in memory are allocated.

records_in_range uses floats to estimate the size of the chunk of the
btree between min and max records, it depends on the btree shape and,
thus, is not portable either. As are optimizer decisions that are based
on records_in_range estimations, if the number happens to be close
to a tipping point.

as a fix, reduce the number of matching rows, so that even with
system-specific variations the optimizer would still pick the
expected plan.

Fixes heap.heap failure (range vs ALL) on ppc64

if ${CRC32_LIBRARY} target has no COMPILE_FLAGS yet,
GET_TARGET_PROPERTY returns COMPILE_FLAGS-NOTFOUND, which
doesn't work very well when it's later fed back into COMPILE_FLAGS.

GET_PROPERTY() returns an empty string in this case.

MDEV-15526 SysV init service deployed file '/etc/init.d/mysql' prevents systemctl disable command to work correctly (mariadb|mysql naming support) (debian/ubuntu)

mariadb service is controlled by systemd

Do not install SysV init script on Debian/Ubuntu in /etc/init.d/
put it in /usr/share/mysql in case the user would need it for something.

Use systemctl in pre/post scripts directly
without funky conditionals and wrapper scripts

fixes
MDEV-14732 mysql.db privileges evaluated on order of grants rather than hierarchically
MDEV-8269 Correct fix for Bug #20181776 :- ACCESS CONTROL DOESN'T MATCH MOST SPECIFIC HOST WHEN IT CONTAINS WILDCARD

reimplement the old ad hoc get_sort() function to use a wildcard
pattern ordering logic that works correctly in may be all practical cases.

get_sort() is renamed to catch merge errors at compilation time.
moved to a separate included file, because of a long comment.

username can be empty, meaning anybody, or must match literally.
only db and host names are matched with wildcards.

Server and command line tools now support option --tls_version to specify the
TLS version between client and server. Valid values are TLSv1.0, TLSv1.1, TLSv1.2, TLSv1.3
or a combination of them. E.g.

--tls_version=TLSv1.3
--tls_version=TLSv1.2,TLSv1.3

In case there is a gap between versions, the lowest version will be used:
--tls_version=TLSv1.1,TLSv1.3 -> Only TLSv1.1 will be available.

If the used TLS library doesn't support the specified TLS version, it will use
the default configuration.

Limitations:

SSLv3 is not supported. The default configuration doesn't support TLSv1.0 anymore.
TLSv1.3 protocol currently is only supported by OpenSSL 1.1.0 (client and server) and
GnuTLS 3.6.5 (client only).

Overview of TLS implementations and protocols

Server:

+-----------+-----------------------------------------+
| Library   | Supported TLS versions                  |
+-----------+-----------------------------------------+
| WolfSSL   | TLSv1.1, TLSv1,2                        |
+-----------+-----------------------------------------+
| OpenSSL   | (TLSv1.0), TLSv1.1, TLSv1,2, TLSv1.3    |
+-----------+-----------------------------------------+
| LibreSSL  | (TLSv1.0), TLSv1.1, TLSv1,2, TLSv1.3    |
+-----------+-----------------------------------------+

Client (MariaDB Connector/C)
+-----------+-----------------------------------------+
| Library   | Supported TLS versions                  |
+-----------+-----------------------------------------+
| GnuTLS    | (TLSv1.0), TLSv1.1, TLSv1.2, TLSv1.3    |
+-----------+-----------------------------------------+
| Schannel  | (TLSv1.0), TLSv1.1, TLSv1.2             |
+-----------+-----------------------------------------+
| OpenSSL   | (TLSv1.0), TLSv1.1, TLSv1,2, TLSv1.3    |
+-----------+-----------------------------------------+
| LibreSSL  | (TLSv1.0), TLSv1.1, TLSv1,2, TLSv1.3    |
+-----------+-----------------------------------------+

fix a typo

followup for 6e5c2466

When compiling with -DEXTRA_DEBUG and run main.stat_tables_missing
on go the warning:
Warning:  Table: ./mysql/column_stats is open on rename old_table

This happened because rename_table_in_stat_tables() re-open the
table that was to be renamed.
Fixed by moving update of stat tables after all renames has been made.

MDEV-19634: Assertion `0' failed in row_sel_convert_mysql_key_to_innobase, [Warning] InnoDB: Using a partial-field key prefix in search

For a key with keyparts (k1,k2,k3) , if we are building a range over the keyparts
we should make sure that if min_value/max_value for a keypart is not added to
key buffer then the keyparts following should also not be allowed.

documentation


Apparently, WolfSSL wants to have *exactly* the same defines for
the user of the library as the was when building library itself.

A lot of #defines have an impact on ABI (structure sizes, alignment etc)

Co-Authored-By: grooverdan <daniel@linux.ibm.com>

By removing Galera functionality, we remove PermissionsStartOnly=true
and hence make this service more flexible for running multiple
instances each on a different user.

When the multi-instance systemd service file was chosen it effectively
relied on /etc/my.cnf.d/my{instancename}.cnf file to define its
configuration file. This is problematic if running along side a
single instance mariadb service which has /etc/my.cnf that reads all
configuration file /etc/my.cnf.d/*.cnf.

To prevent the service from auto starting up if a user has this
previous configuration ConditionPathExists=!@sysconf2dir@/my%I.cnf
to ensure that a user with the previous configuration isn't
started in a non-intended mode. Documentation in the service file
(should be release notes too), described a recommended migration.

A new approach was to use --defaults-group-suffix=.%I as an
arguement to mysqld and let the user define a [mysqld.{instancename}]
group within the configuration file. This way existing global
mysqld configuration options are read with the instance name
having special overrides of datadir, port, socket etc.

A systemd environment variable MYSQLD_MULTI_INSTANCE is used in the
defination as it give the user flexability to use multiple
segregation mechanisms between services. This is used multiple
times within the service which all needed to be kept consistent.

Another notable change is mysql_install_db being part of the
ExecStartPre. This provides and auto-initialization for users
that run multiple instances.

when copying the TREE, take into account that init_tree can
internally adjust tree->size_of_element

Closes #830

On 32-bit systems, sizeof(uint)==sizeof(long).
The C++11 narrowing cast would issue a warning due to the sign mismatch.

If the allocation of spider_table_sts_threads failed,
we would DBUG_RETURN(error_num) without having initialized
it earlier.

Pre-initialize error_num to HA_ERR_OUT_OF_MEM and remove
a lot of assignments that thus became redundant.

This error was introduced in 207594af
(Spider 3.3.13).

Problem:
=========
One of the purge thread access the corrupted page and tries to remove from
LRU list. In the mean time, other purge threads are waiting for same page
in buf_wait_for_read(). Assertion(buf_fix_count == 0) fails for the
purge thread which tries to remove the page from LRU list.

Solution:
========
- Set the page id as FIL_NULL to indicate the page is corrupted before
removing the block from LRU list. Acquire hash lock for the particular
page id and wait for the other threads to release buf_fix_count
for the block.

- Added the error check for btr_cur_open() in row_search_on_row_ref().

Before killing the server, ensure that the incomplete state of
the transaction will be made durable and will be applied and
rolled back on recovery, so that each time, roughly the same
amount of work will be done.

Remove DML statements after the recovery, and execute
CHECK TABLE instead.