Fix for 'reorder' compiler warning.

MariaDB Galera server's (MGC) handlerton & THD structures have
some extra wsrep members as compared to MariaDB server. As a
result, when plugins from packages, built along with MariaDB
server like Connect & OQGraph are loaded and accessed by MGC,
the objects may get initialized improperly.

Fixed by moving the wsrep-additions to the end of the structure.

Enable replication of GRANT/REVOKE ROLE commands across
galera nodes.

Remove master-bin.state file on joiner node during SST.

Try not to release 0 (STDIN_FILENO) file descriptor as it can
incorrectly get reused by streams opened later.

* Wait for aborted thd (victim) to release MDL locks
* Skip aborting an already aborted thd
* Defer setting OK status in case of CTAS
* Minor cosmetic changes
* Added a test case

Set thd's state to 'committed' only after it has done closing tables
(called indirectly by relay_group_info::cleanup_context()).

Add SELinux policy and AppArmor profile under policy/.

fix the test case for ps-protocol

MDEV-5977 MariaDB 10.0 is not installable on Trusty when "trusty-updates universe" is in sources.list

fix upgrade[2] tests on trusty and utopic: add missing
conflicts/replaces, client-10.0 should conflict/replace client-5.5.

reformat other conflicts/replaces lines to make them easier
to read and merge

in ha_delete_table()
* only convert ENOENT and HA_ERR_NO_SUCH_TABLE to warnings
* only return real error codes (that is, not ENOENT and
  not HA_ERR_NO_SUCH_TABLE)
* intercept HA_ERR_ROW_IS_REFERENCED to generate backward
  compatible ER_ROW_IS_REFERENCED

in mysql_rm_table_no_locks()
* no special code to handle HA_ERR_ROW_IS_REFERENCED
* no special code to handle ENOENT and HA_ERR_NO_SUCH_TABLE
* return multi-table error ER_BAD_TABLE_ERROR <table list> only
  when there were many errors, not when there were many
  tables to drop (but only one table generated an error)

in cmake tests let's treat clang like gcc (same options,
same builtins) in many cases.

* don't check the compiler when
  * testing for -fvisibility=hidden support
  * testing for HAVE_ABI_CXA_DEMANGLE
  * testing for HAVE_GCC_ATOMIC_BUILTINS
  * when removing options with string(replace)
  * when running ${CC} --version (ignore the error instead)
* run ABI checks for clang
* use "canonical" gcc flags for clang
* fix groonga too

Also:

* add cmake detection for gcc __atomic_* builtins. they might be
  supported (__ATOMIC_SEQ_CST is defined), but not for all operand
  sizes. In particular, 64-bit atomic load is problematic on i386
* cache check results for Windows
* remove the test for HAVE_CXXABI_H (HAVE_ABI_CXA_DEMANGLE is
  suffifient)

* new mysqldump option
* add more engines to the "external data engines" list
* redo the check to be able to print the list of engines in --help

in innobase: compilation error on windows
other changes: perfschema merge followup

only columns really stored to database.

When RENAME TABLE is executed, it apparently does not check whether the engine
is available (unlike ALTER TABLE .. RENAME, which does). It means that if the
engine in question was not loaded on some reason, the table might become
unusable, since the engine won't know about the change.

With this patch RENAME TABLE fails if storage engine is not available.

Put client plugins into -common rpm, not -shared.
Because they're needed for
* all clients that link with shared libmysqlclient (-shared)
* our clients from -client rpm, they're statically linked (-client)
* the server that acts as a replication slave (-server)

MDEV-7871 Tests fail massively on "Assertion `status_var.memory_used == 0'" when run with --ps --embedded.
   As the MF_THREAD_SPECIFIC was introduced to the alloc_root's and
   the prealloc added to the statement::mem_root and statement::result.alloc, we have to adjust
   the embedded server to it. The preallocation was removed for the embedded server as it
   makes no sence for it. The msyqltest should free the statement inside the proper thead to
   make the memory statistics happy.

MDEV-8131 MariaDB does not build on hurd-i386: plugin/auth_dialog/dialog.c:172:20: error: 'RTLD_DEFAULT' undeclared

define _GNU_SORUCE before including dlfcn.h

when --bind-address is not specificed explicitly (or set to '*')
MariaDB tries all wildcard addresses. Print a warning (not an error)
if a socket cannot be created for some of them.

Still print an error if a socket cannot be created for an address
that a user has specified expicitly with --bind-address.

disable IPv6 globally in mysql-test, only use it
in dedicated IPv6 tests (where it is enabled per-test)