The problem was increment of aborted_threads variable due to thd->killed which was set when threadpool connection was terminated .  The fix is not to set thd->killed anymore, there is no real reason for doing it..

Added a test that checks that status variable aborted_clients does not grow for ordinary disconnects, and that successful KILL increments this variable.

  Points and lines should disappear if we got negative D.
  To make it work properly inside the GEOMETRYCOLLECTION,
  we add the empty operation there.

bug #986977 Assertion `!cur_p->event' failed in Gcalc_scan_iterator::arrange_event(int, int).
  The double->inernal coord conversion produced -0 (minus zero) on some data.
  That minus-zero produces invalid comparison results when compared agains plus-zero.
  So we fixed the gcalc_set_double() to avoid it.

per-file comments:
  mysql-test/r/gis-precise.result
        result updated.
  mysql-test/t/gis-precise.test
        tests for #977021 and #986977 added.
  sql/gcalc_slicescan.cc
        bug #986977. The gcalc_set_double fixed to not produce minus-zero.
  sql/item_geofunc.cc
        bug #977021. Add the NOOP for the disappearing features.

MDEV-217 - Assertion `thd->stmt_arena != thd->progress.arena' failed in thd_progress_init on OPTIMIZE two tables when replaced by recreate

call thd_progress_end() in the copy_data_between_tables(), to match its
thd_progress_init().

for a plugin installed run-time

(--xxx=ON behaving as --xxx=FORCE)

This can result in bad deadlocks (e.g loader lock), seen in latest crash reports.

since password characters can contain quotes or spaces.

The proper quoting method for command line arguments used here was  extracted from
http://blogs.msdn.com/b/twistylittlepassagesallalike/archive/2011/04/23/everyone-quotes-arguments-the-wrong-way.aspx

Additionally, mysql_install_db.exe now passes root password to "mysqld.exe --bootstrap"
 in hexadecimal form, to handle potential special chars inside password string literal.

Also, do not package aria log files in the zip package- not required for the database to function, 
also will avoid trouble with recovery, if someone  accidentially (or on purpose) upgrades by unpacking the zip in the existing install directory.

threads are retrieving events at the same time.

- Workaround linker bug that prevents linking aria test executables
   using -fno-common on OSX
- Skip system readline detection (OSX readline is incompatible one)
- Make Xcode generator work

(see my comments starting from [9 Apr 22:18])

The previous patch for the bug (that erroneously identified the bug as
bug 972973 in its comment) was incorrect. 
It turned out that the code that triggered the abort complain reported for
the bug was not needed at all.

When the function free_tmp_table deletes the handler object for
a temporary table the field TABLE::file for this table should be
set to NULL. Otherwise an assertion failure may occur.

This bug happened because the function find_field_in_view formed
autogenerated names of view columns without a possibility to roll
them back. In some situation it could cause memory misuses reported
by valgrind or even crashes.