MDEV-7000 Assertion `0' failed in Protocol::end_statement() on executing DDL under innodb_fake_changes=1

correct the if() condition to match the behavior of the old code
that this if() was supposed to replace

There were two issues:

* set_var_default_role::user was overwritten with a new value,
  allocated in the thd->mem_root, which is reset between executions.
  That was causing the crash. Solved by introducing set_var_default_role::real_user

* when privilege tables were opened on EXECUTE, the reprepare_observer
  would abort the statement (as privilege tables are opened using
  the local TABLE_LIST that doesn't preserve metadata from PREPARE, so
  reprepare_observer thought they're changed). This issue also applied
  to SET PASSWORD. Solved by disabling reprepare_observer.

Added logic to sort gtid list based on domain_id before
populating them in string. Added a test case.

Removed 'galera-sst-mode' option from mysqldump and added logic
in wsrep_sst_mysqldump script to retrieve gtid_binlog_state from
donor node and send it to the joiner node.

Added an include file to check galera library version.

* Changed loopback detection to be done via ifa->ifa_flags
* Removed unused function wsrep_guess_address()

by adding a new class String_copier.

This is a pre-requisite patch for MDEV-6566 and MDEV-6572,
to avoid adding more similar code.

Create_tmp_table was called incorrectly called in
select_materialized_with_stats::create_result_table, having keep_row_order
passed for the do_not_open parameter and keep_row_order always set to false.

file_key_management_plugin is used

Fixed error handling and added disabling InnoDB redo log encryption
if encryption key management plugin is not there.

- Remove the compiler warning, add assert statements.
- make select_describe() not call mysql_explain_union() for
  views that were "merged for INSERT".

file_key_management_plugin is used

Fixed error handling and added disabling InnoDB redo log encryption
if encryption key management plugin is not there.

of encryption/compression pages and that will happen if and only
if dirty pages are written to the disk.

    MDEV-7399: Add support for INFORMATION_SCHEMA.INNODB_MUTEXES
    MDEV-7618: Improve semaphore instrumentation

    Introduced two new information schema tables to monitor mutex waits
    and semaphore waits. Added a new configuration variable
    innodb_intrument_semaphores to add thread_id, file name and
    line of current holder of mutex/rw_lock.

Added support for compression method snappy for page compression.

Changed wsrep plugin from mysql_plugin to maria_plugin to
set up plugin_maturity to Stable.

encrypted tables

Introduced a new innodb_default_page_encryption_key configuration
variable to allow user to set the default key identifier.

put cracklib_password_check into a separate package.
build it conditionally on Debian/Ubuntu

namely, remove the code to support:
etch, lenny, hardy, intrepid, jaunty, karmic, maverick, natty

Remove ONLY_IF clause in MYSQL_ADD_PLUGIN and the requirement
that every plugin's CMakeLists.txt *must* do MYSQL_ADD_PLUGIN
for PLUGIN_XXX=YES to work. This was very fragile and cannot be
relied on.

Use a different implementation of =YES check - iterate all
PLUGIN_* variables and see which one doesn't have a matching target.

Revert all ONLY_IF changes in CMakeLists.txt files.

we don't want mysys static data structures to be overwritten
when a dynamic plugin is loaded.

This reverts commit aa61e4c7
that broke the compilation on few platforms (e.g. centos5).

These warnings are already fixed properly in 10.0-connect.

workaround, not a fix: don't build key management plugins in yassl builds

when page compression and google encryption is used.