SET slow_query_log and failed connection attempt

A very subtle though valid deadlock. Deadlock chain:
wrlock(LOCK_grant)    -> lock(acl_cache->lock) GRANT/REVOKE CREATE/DROP USER
lock(LOCK_open)       -> rdlock(LOCK_grant)    SELECT * FROM I_S.COLUMNS
wrlock(LOCK_logger)   -> lock(LOCK_open)       SET @@global.slow_query_log='ON'
lock(acl_cache->lock) -> rdlock(LOCK_logger)   Failed connection

Fixed by removing relationship between acl_cache->lock and LOCK_logger
during failed connection attempt.

mysql-test/r/func_group.result:
  Test case
mysql-test/t/func_group.test:
  Test case
sql/item_sum.cc:
  Restore ORDER for prepared statements

and other fixes for gcc-4.9.1 on sid

don't install them at all

don't send an OK packet if the SHOW PROCESSLIST was killed

* remove bundled jemalloc, use the system one
* force jemalloc in release builds on linux

bits were inconsistent though the handle was opened without those bits
set. This caused dbremove to always fail.

Avoided exponential recursive calls of JOIN_CACHE::join_records() in the case
of non-nested outer joins.
A different solution is required to resolve this performance problem for
nested outer joins.

fix readline/libedit detection:
* search in readline/, editline/ and edit/readline/
* fix typos CMAKE_REQUIRES_LIBRARIES -> CMAKE_REQUIRED_LIBRARIES
* use correct libedit API
* use different cmake variables for libedit and readline

FT-591 fix valgrind uninitialized value error in block allocator test caused by reading past the end of a the blockpair array

MDEV-6605 Multiple Clients Inserting Causing Error: Failed to read auto-increment value from storage engine

* handler::get_auto_increment() was not expecting any errors from the storage engine.
  That was wrong, errors could happen.
* ha_partition::get_auto_increment() was doing index lookups in partition under a mutex.
  This was redundant (engine transaction isolation was covering that anyway)
  and harmful (causing deadlocks).

if it has to be a mess of ifdefs, then mess of ifdefs it is

MDEV-6595 [PATCH] HPPA: storage/xtradb/os/os0stacktrace.c:88:54: error: invalid operands to binary & (have 'void *' and 'long unsigned int')

fix precedence as in the patch from Brian Evans

this variable scope is Global, Session
type is boolean and default value is TRUE

FT-273 Prevent setting the memcmp magic on db handles for which a FT is already open. Improve comments. Add a test.

  if it's run on a real disk
  
  Made test smaller.