main.mysqlhotcopy_myisam cannot find mysqlhotcopy tool

wsrep scripts are not executable in CMAKE_CURRENT_BINARY_DIR

* generate and install mysql_config
* symlink mariadb_config (from C/C) to mariadb-config

also:
* .gitignore generated mariadb-config.1
* remove obsolete compiler flag from C/C

This reverts commit 5d1b8f41.

because since 306e439c manpages use troff aliases
instead of symlinks, so they should not be symlinked.

Drop excess jobs while still making sure there is a good variation of
running all test suites, gcc and clang versions.

Also introduce testing on architectures arm64 and ppc64le.

- Properly define build dependencies via addons/homebrew, but still keep
  secondary Homebrew run until OS X builds fully work.
- Remove references to OS X bugs that are already closed.
- As long as the OS X build does not work, it is enough to attempt to run
  just one of them, no need for many in parallel. It will just waste
  resources and slow down the job from finishing quickly.

This further simplifies and cleans up the Travis-CI file without making
any major functional changes.

With this structure .travis.yml is much easier to read and thanks to the
added documentation next developers are less likely to mess it up again
as they can more easily see how the jobs matrix work.

Number of jobs:
- before: 33 (with 7 ignored)
- after:  33 (with 7 ignored)

This partially reverts commits c12609dd and 193bc89a.

Remove unnecessary dependencies that nothing uses: dpatch libzmq-dev

Install extra build dependencies from a PPA specifically tailored for
Travis-CI use and which ensures all architectures are supported (in this
case s390x is needed and was not available from mariadb.org repos).

Validated with https://config.travis-ci.com/explore

This is first step in refactoring the Travis-CI file, which had become a
mess. This commit has no functional changes, just syntactical cleanup
and simplification.

Dependencies list has not changes, it is just sorted alphabetically so
it is easier to compare to e.g. debian/control file list.

innodb_init_params(): make sure that srv_n_log_files == 1 always

MDEV-22012 Allow SET TIMESTAMP for users with GRANT BINLOG REPLAY when --secure-timestamp=replication

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.

btr_blob_free(): Compare page_id_t directly.

buf_pool_watch_unset(): Avoid unnecessarily buf_pool.mutex acquisition.

Clean up some comments as well.

Remove unnecessary buf_pool_t:: qualifiers. In comments,
replace buf_pool::mutex with buf_pool.mutex.

Remove an outdated comment about a planned buffer pool resizing feature.
It is already implemented in MariaDB 10.2.2 (and MySQL 5.7.9).

- mbmaxlen is always 0 for binary field. Ignore the assert of checking
field->prefix_len % field->col->mbmaxlen == 0.

fix manpages in Debian

To change all executables to have a mariadb name I had to:
- Do name changes in every CMakeLists.txt that produces executables
- CREATE_MARIADB_SYMLINK was removed and GET_SYMLINK added by Wlad to reuse the function in other places also
- The scripts/CMakeLists.txt could make use of GET_SYMLINK instead of introducing redundant code, but I thought I'll leave that for next release
- A lot of changes to debian/.install and debian/.links files due to swapping of real executable and symlink. I did not however change the name of the manpages, so the real name is still mysql there and mariadb are symlinks.
- The Windows part needed a change now when we made the executables mariadb -named. MSI (and ZIP) do not support symlinks and to not break backward compatibility we had to include mysql named binaries also. Done by Wlad

my_atomic.h is included indirectly anyways.

The code that commit bb24fa31
moved to a separate file assume_aligned.h was introduced in
commit 25e2a556 and developed
by employees of MariaDB Corporation.

* Remove dead code

* MDEV-21675 Data inconsistency after multirow insert rollback

This patch fixes data inconsistencies that happen after rollback of
multirow inserts, with binlog disabled.
For example, statements such as `INSERT INTO t1 VALUES (1,'a'),(1,'b')`
that fail with duplicate key error. In such cases the whole statement
is rolled back. However, with wsrep_emulate_binlog in effect, the
IO_CACHE would not be truncated, and the pending rows events would be
replicated to the rest of the cluster. In the above example, it would
result in row (1,'a') being replicated, whereas locally the statement
is rolled back entirely. Making the cluster inconsistent.
The patch changes the code so that prior to statement rollback,
pending rows event are removed and the stmt cache reset.
That patch also introduces MTR tests that excercise multirow insert
statements for regular, and streaming replication.

Also, clean up the test innodb_gis.geometry a little further.

Remove CREATE/DROP database.

Remove some unnecessary suppressions, replacements, and
SQL statements.

Populate tables via have_sequence.inc to avoid the creation of
explicit InnoDB record locks in INSERT...SELECT. This will remove
some gaps in AUTO_INCREMENT values.

After MDEV-12353, the consistency check that I originally added for
commit 1b9fe0bb
(InnoDB Plugin for MySQL 5.1) started randomly failing.

It turns out that the IMPORT TABLESPACE code was always incorrect:
it did not update the (redundantly stored) tablespace ID
in index tree root pages. It only does that for page headers
and BLOB pointers.

PageConverter::update_index_page(): Update the tablespace ID
in the BTR_SEG_TOP and BTR_SEG_LEAF of index root pages.

Forcing wait on nodes 2 and 3, to turn wsrep_ready to 'ON' before querying wsrep status variables.
This guarantees that status reads don't come too early on these nodes