The problem is that MySQL use of pthread_setschedprio is not
supported by i5/OS and the default system behavior for unsupported
calls is to emit a SIGILL signal which causes the server to
abort.

The solution is to treat the pthread_setschedprio as inexistent
when compiling binaries for i5/OS. This also does not invalidate
the fix for bug 38477 as the only supported dispatch class is
SCHED_OTHER (which is passed to pthread_setschedparam).

 - Allow the new process to break away from any job that this
   process is part of so that it can be assigned to the new JobObject
   we just created. This is safe since the new JobObject is created with
   the JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE flag, making sure it will be
   terminated when the last handle to it is closed(which is owned by
   this process).

+ minor improvements

Documented behaviour was broken by the patch for bug 33699
that actually is not a bug.

This fix reverts patch for bug 33699 and reverts the
UPDATE of NOT NULL field with NULL query to old
behavior.

            ORDER BY could cause a server crash

Dependent subqueries like

  SELECT COUNT(*) FROM t1, t2 WHERE t2.b
   IN (SELECT DISTINCT t2.b FROM t2 WHERE t2.b = t1.a)

caused a memory leak proportional to the
number of outer rows.


The make_simple_join() function has been modified to
JOIN class method to store join_tab_reexec and
table_reexec values in the parent join only
(make_simple_join of tmp_join may access these values
via 'this' pointer of the parent JOIN).

NOTE: this patch doesn't include standard test case (this is
"out of memory" bug). See bug #42037 page for test cases.

Problem: some queries using NAME_CONST(.. COLLATE ...)
lead to server crash due to failed type cast.

Fix: return the underlying item's type in case of
NAME_CONST(.. COLLATE ...) to avoid wrong casting.

   code backported from 6.0


per-file messages:
  include/my_global.h
    Remove SC_MAXWIDTH. This is unused and irrelevant nowadays.
  include/my_sys.h
    Remove errbuf declaration and unused definitions.
  mysys/my_error.c
    Remove errbuf definition and move and adjust ERRMSGSIZE.
  mysys/my_init.c
    Declare buffer on the stack and use my_snprintf.
  mysys/safemalloc.c
    Use size explicitly. It's more than enough for the message at hand.
  sql/sql_error.cc
    Use size explicitly. It's more than enough for the message at hand.
  sql/sql_parse.cc
    Declare buffer on the stack. Use my_snprintf as it will result in
    less stack space being used than by a system provided sprintf --
    this allows us to put the buffer on the stack without causing much
    trouble. Also, the use of errbuff here was not thread-safe as the
    function can be entered concurrently from multiple threads.
  sql/sql_table.cc
    Use MYSQL_ERRMSG_SIZE. Extra space is not needed as my_snprintf will
    nul terminate strings.
  storage/myisam/ha_myisam.cc
Use MYSQL_ERRMSG_SIZE.
  sql/share/errmsg.txt
    Error message truncation in test "innodb" in embedded mode
    filename in the error message can safely take up to 210 symbols.

Accessing well defined MERGE table may return an error
stating that the merge table is incorrectly defined. This
happens if MERGE child tables were accessed before and we
failed to open another incorrectly defined MERGE table in
this connection.

myrg_open() internally used my_errno as a variable for determining
failure, and thus could be tricked into a wrong decision by other
uses of my_errno.

With this fix we use function local boolean flag instead of my_errno
to determine failure.

Problem:
   RelativeLocationPath can appear only after a node-set expression
   in the third and the fourth branches of this rule:
     PathExpr :: =  LocationPath
                    | FilterExpr
                    | FilterExpr '/' RelativeLocationPath
                    | FilterExpr '//' RelativeLocationPath
   XPatch code didn't check the type of FilterExpr and crashed.
Fix:
   If FilterExpr is a scalar expression
   (variable reference, literal, number, scalar function call)
   return error.

fixing build issue, caused by the previous push.

            
The bug happened because filtering-out a STMT_END_F-flagged event so that
the transaction COMMIT finds traces of incomplete statement commit.
Such situation is only possible with ndb circular replication. The filtered-out
rows event is one that immediately preceeds the COMMIT query event.
      
Fixed with deploying an the rows-log-event statement commit at executing
of the transaction COMMIT event. 
Resources that were allocated by other than STMT_END_F-flagged event of
the last statement are clean up prior execution of the commit logics.

 - Properly set --bindir=$path_client_bindir and --basedir=$basedir by adding %s format specifier

                    functions
      
String::realloc() did not check whether the existing string data fits in the newly
allocated buffer for cases when reallocating a String object with external buffer
(i.e.alloced == FALSE).  This could lead to memory overruns in some cases.

           upgrading lock, even with low_priority_updates

The problem is that there is no mechanism to control whether a
delayed insert takes a high or low priority lock on a table.

The solution is to modify the delayed insert thread ("handler")
to take into account the global value of low_priority_updates
when taking table locks. The value of low_priority_updates is
retrieved when the insert delayed thread is created and will
remain the same for the duration of the thread.

+ fix wrong resultfile have_outfile.require