only present in the Galera tree

Fix for some compiler warnings.

```---------------------------------------------------------
revno: 3942
committer: Seppo Jaakola <seppo.jaakola@codership.com>
branch nick: wsrep-5.5-23
timestamp: Thu 2013-11-07 17:37:10 +0200
message:
  References: lp:1248921 - checking if index is foreign earlier to adhere to lat
ch order protocol
```

---------------------------------------------------------
revno: 3941
fixes bug: https://launchpad.net/bugs/1248908
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Thu 2013-11-07 14:31:04 +0200
message:
  References lp:1248908 - Fixed access to trx sys header
    
  Pass trx sys header as argument for trx_sys_update_wsrep_checkpoint()
  and trx_sys_update_mysql_binlog_offset() to avoid successive calls
  to trx_sysf_get().
------------------------------------------------------------
revno: 3940
fixes bug: https://launchpad.net/bugs/1244100
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Tue 2013-11-05 15:31:12 +0200
message:
  References lp:1244100 - assign value for check_purge before return
------------------------------------------------------------
revno: 3939
fixes bug: https://launchpad.net/bugs/1247978
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Tue 2013-11-05 01:01:36 +0200
message:
  References lp:1247978 - force release transactional MDL locks if wsrep is on a
nd no active transaction at the end of mysql_execute_command()
------------------------------------------------------------
revno: 3938
committer: Vladislav Klyachin <vladislav.klyachin@codership.com>
branch nick: 5.5-23
timestamp: Sun 2013-11-03 20:48:06 +0400
message:
  References lp:1232789 - fix FLUSH STATUS zeroes up wsrep_cluster_size and wsre
p_local_index
------------------------------------------------------------
revno: 3937  5kB/s - 
committer: Vladislav Klyachin <vladislav.klyachin@codership.com>
branch nick: 5.5-23
timestamp: Sun 2013-11-03 17:06:31 +0400
message:
  References lp:587170 - reset auto_increment_* vars to defaults for TOI operati
ons
------------------------------------------------------------
revno: 3936
committer: Vladislav Klyachin <vladislav.klyachin@codership.com>
branch nick: 5.5-23
timestamp: Sun 2013-11-03 00:10:45 +0400
message:
  References lp:1072839 - fix for memory leaks with wsrep variables
------------------------------------------------------------
revno: 3935
committer: Seppo Jaakola <seppo.jaakola@codership.com>
branch nick: wsrep-5.5-23
timestamp: Wed 2013-10-30 14:34:32 +0200
message:
  References: lp:1246257 - skipping replication for CREATE TEMPORARY TABLE LIKE.
..  constructs
------------------------------------------------------------
revno: 3934  6kB/s \ 
fixes bug: https://launchpad.net/bugs/1241760
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Mon 2013-10-28 11:01:53 +0200
message:
  References lp:1241760 - save thd->db to wsrep_thd_shadow before replay
------------------------------------------------------------
revno: 3933
fixes bug: https://launchpad.net/bugs/1206129
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Sun 2013-10-27 18:15:12 +0200
message:
  References lp:1206129 - check binlog_hton->commit() return value, call wsrep_p
ost_commit() instead of wsrep_cleanup_transaction()
------------------------------------------------------------
revno: 3932
fixes bug: https://launchpad.net/bugs/1244661
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Sun 2013-10-27 13:14:02 +0200
message:
  References lp:1244661 - added wsrep_register_hton() to trans_rollback_implicit
()
------------------------------------------------------------
revno: 3931
fixes bug: https://launchpad.net/bugs/1244667
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Sun 2013-10-27 11:08:49 +0200
message:
  References lp:1244667 - restore thd->server_status after replay

```---------------------------------------------------------
revno: 3929 [merge]
fixes bug: https://launchpad.net/bugs/1243150
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Wed 2013-10-23 20:05:01 +0300
message:     8kB/s - 
  References lp:1243150 - initial wsrep hton cleanups
  
  * Removed wsrep_seqno_changed boolean
  * wsrep_cleanup_transaction() is now called explicitly whenever it is
    clear that transaction has come to an end
  * wsrep_trans_cache_is_empty() now checks from cache_mngr recardless of
    command type
  * Separated call to wsrep->post_commit() to own function, called from
    transaction.cc whenever appropriate
  * wsrep_thd_is_brute_force() now investigates only thd->wsrep_exec_mode
  * More comments and debug time assertions
  * Debug code to check that wsrep position stored in InnoDB is
    monotinically increasing. Enabled with UNIV_DEBUG
```

---------------------------------------------------------
revno: 3928
fixes bug: https://launchpad.net/bugs/1237889
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Tue 2013-10-22 22:01:20 +0300
message:
  References lp:1237889 - reverting fix in r3926, it broke crash recovery
------------------------------------------------------------
revno: 3927
fixes bug: https://launchpad.net/bugs/1240040
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Tue 2013-10-15 14:46:15 +0300
message:
  References lp:1240040 - added WSREP_MYSQL_DB as a key for DROP VIEW
------------------------------------------------------------
revno: 3926
fixes bug: https://launchpad.net/bugs/1237889
committer: Teemu Ollakka <teemu.ollakka@codership.com>
branch nick: 5.5-23
timestamp: Thu 2013-10-10 14:22:58 +0300
message:
  References lp:1237889 - register wsrep hton only if thd->wsrep_exec_mode == LO
CAL_STATE
------------------------------------------------------------
revno: 3925
fixes bug: https://launchpad.net/bugs/1235635
committer: Alexey Yurchenko <alexey.yurchenko@codership.com>
branch nick: 5.5-23
timestamp: Sat 2013-10-05 18:03:06 +0300
message:
  References lp:1235635 - fixed the warning by initializing c_lock to NULL.

This patch fixes both the reported issues :
(1) Included '-wsrep' to the server version information.

> select @@version;
+-----------------------------+
| @@version                   |
+-----------------------------+
| 5.5.33a-MariaDB-wsrep-debug |
+-----------------------------+

(2) The @@version_comment would no longer have XXXX
in the wsrep version information in case cmake couldn't
determine the current bzr revision.

            -DINSTALL_SYSCONFDIR/-DDEFAULT_SYSCONFDIR specified

The reason for a bug is in support-files/CMakeLists.txt that tries to
install files in INSTALL_SYSCONF2DIR, without checking whether this
variable is actually defined. 

Normally INSTALL_SYSCONF2DIR is always defined if INSTALL_SYSCONFDIR is
defined, and support-files/CMakeLists.txt assumes that. But when one
specifies INSTALL_SYSCONFDIR manually on the command line, this
assumption might be broken.

(some patches reverted, test case added)

sort xtradb status variables

MDEV-5069: Server crashes in SEL_ARG::increment_use_count with index_merge+index_merge_sort_union, FORCE INDEX
- Don't call incr_refs() is the merged SEL_ARG* is NULL.

Added test case for new system variable innodb_use_stacktrace and made sure that it can be used only on startup. Fixed compiler problems on solaris and other platforms that do not contain necessary headers and functions.

MDEV-5247: DB locked up at btr0cur.c line 568. Additional fixes to inconsistent usage of have_LRU_mutex and added additional debug assertions to guard incorrect usage of this mutex. Fixes issues found on additional testing and mysql test suite.

This bug was a consequence of the incorrect fix for bug mdev-5091.

Fix compiler error introduced on revision 3937, make sure that stackdump is compiled only on __linux__.

mysql_tzinfo_to_sql is not compiled under Windows in the pre-5.5 versions.
Do not set the MYSQL_TZINFO_TO_SQL variable in the version prior to 5.5
under Windows.

MDEV-5247: DB locked up at btr0cur.c line 568. There is inconsistent and non logical usage of have_LRU_mutex and incorrect value on ha_innodb.cc when buf_LRU_free_block is called. Additionally, for future long semaphore wait cases added a new configuration variable innodb_use_stacktrace. If this variable is true a signal handler for SIGUSR2 is installed when InnoDB server starts and when a long semaphore wait is detected at sync/sync0array.c we send SIGUSR2 signal to waiting thread and thread that has acuired RW-latch. For both threads a full stacktrace is produced as well as its is possible.

The function SELECT_LEX::update_used_tables should process all
ORDER BY lists in any subselect of a union.

Allow only one level of symlink recursion in mysql_tzdata_to_sql,
to avoid infinite loops.

Apply fix suggested by Igor:
- When eliminate_item_equal() generates pair-wise equalities from a 
  multi-equality,  do generate a "bridge" equality between the first 
  field inside SJM nest and the field that's first in the overall multi-equality.

MDEV-5113 Wrong result (extra row) and valgrind warnings in Item_maxmin_subselect::any_value on 2nd execution of PS with SELECT subquery

When setting Item_func_not_all::test_sum_item or Item_func_not_all::test_sub_item,
reset the other one to NULL - they can never be set both. When a PS is reexecuted,
different executions might be optimized differently and a wrong test_su*_item
might stay set from the previous execution.

- MIN/MAX optimizer does a check whether a "field CMP const" comparison uses a constant 
  that's longer than the field it is compared to.  Make this check only for string columns,
  also compare character lengths, not byte lengths.