don't transform Item_func_nullif if it's context_analysis_only

when calculating COUNT(basic_const), take into account that
this basic_const may be NULL

This fixes
MDEV-9538 Server crashes in check_show_access on SHOW STATISTICS
MDEV-9539 Server crashes in make_columns_old_format on SHOW GEOMETRY_COLUMNS
MDEV-9540 SHOW SPATIAL_REF_SYS and SHOW SYSTEM_VARIABLES return empty results with numerous warnings

when doing set_field_to_new_field (from switch_to_nullable_trigger_fields())
make sure that the field we're about to change actually belongs
to the right table (otherwise we cannot dereference new_field[]
array as the wrong table might have more fields than
new_field[] has elements)

Case: table with a NOT NULL field, BEFORE UPDATE trigger,
and UPDATE with a subquery that uses GROUP BY on that
NOT NULL field, and needs a temporary table for it.

Because of the BEFORE trigger, the field becomes nullable
temporarily. But its Item_field (used in GROUP BY) doesn't.
When working with the temptable some code looked at
item->maybe_null, some - at field->null_ptr.
The fix: make Item_field nullable when its field is.

This triggers an assert. The group key size is calculated
before the item is made nullable, so the group key doesn't
have a null byte. The fix: make fields/items nullable
before the group key size is calculated.

when replicating old temporal type fields (that don't store
metadata in the binlog), take the precision from
destination fields.

(this fixes the replication failure, crashes were
fixed in a different commit)

it's *display length* (a.k.a. field_length)
not storage length (a.k.a. pack_length)

* make a local variable for target_table->field[col]
* move an often-used bit function to my_bit.h
* remove a non-static and not really needed trivial comparison
  function with a very generic name

to avoid run-time libjemalloc.so dependency
link binary tarballs with a static libjemalloc_pic.a

(-DWITHOUT_SERVER=1)

The filter command did not accept characters . [ ] which are valid
in an attribute name for a sphinx query with json filtering.

+ test case added

BLES (in CREATE_OPTIONS column)

MDEV-9833 - fix mysql_config --libs for weird cases, where mysqlclient link dependencies contain  flags instead of libraries (like  -pthread rather than -lpthread)

Restoring currect_select fixed.

Adjusted INSTALL_LIBDIR detection so that it is set to "lib64" on any 64bit
system (not only x86_64). New condition is insipired by GNUInstallDirs cmake
module.

on FreeBSD 10 jemalloc is in libc, no separate libjemalloc is needed

this simplifies merging of MySQL and TokuDB

"#include <math.h>" has "#define isfinite(X) ..."
while "#include <cmath>" does "#undef isfinite"

in -std=c++11 mode <cmath> is included, we need a workaround
to provide a usable isfinite()

MDEV-9559: Server without encryption configs crashes if selecting from an implicitly encrypted table

There was two problems. Firstly, if page in ibuf is encrypted but
decrypt failed we should not allow InnoDB to start because
this means that system tablespace is encrypted and not usable.
Secondly, if page decrypt is detected we should return false
from buf_page_decrypt_after_read.

            configured withtout username

Federated/spider/connect engines or replication threads connecting to other host
with empty user name may crash mysqld.

This is addition to original patch, which adds a test case and amends a macro.

MDEV-9557 - fix compilation errors due to missing krb5_free_unparsed_name() in old versions of Heimdal Kerberos