Suspected reason for the failure is that safe_process.exe already runs in a job that does not allow breakaways. 
The fix is to use a fallback -  make newly created process the root of the new process group. This allows to kill process together with descendants via GenerateConsoleCtrlEvent (CTRL_BREAK_EVENT, pid)

Several options were not documented
Added missing options and removed a few
Fixed use of --skip-combinations

165 changesets with 23 conflicts:
Text conflict in mysql-test/r/lock_multi.result
Text conflict in mysql-test/t/lock_multi.test
Text conflict in mysql-test/t/mysqldump.test
Text conflict in sql/item_strfunc.cc
Text conflict in sql/log.cc
Text conflict in sql/log_event.cc
Text conflict in sql/parse_file.cc
Text conflict in sql/slave.cc
Text conflict in sql/sp.cc
Text conflict in sql/sp_head.cc
Text conflict in sql/sql_acl.cc
Text conflict in sql/sql_base.cc
Text conflict in sql/sql_class.cc
Text conflict in sql/sql_crypt.cc
Text conflict in sql/sql_db.cc
Text conflict in sql/sql_lex.cc
Text conflict in sql/sql_parse.cc
Text conflict in sql/sql_select.cc
Text conflict in sql/sql_table.cc
Text conflict in sql/sql_view.cc
Text conflict in storage/innobase/handler/ha_innodb.cc
Text conflict in storage/myisam/mi_packrec.c
Text conflict in tests/mysql_client_test.c

Updates to Innobase, taken from main 5.1:
bzr: ERROR: Some change isn't sane:
File mysql-test/r/innodb-semi-consistent.result is owned by Innobase and should not be updated.
File mysql-test/t/innodb-semi-consistent.test is owned by Innobase and should not be updated.
File storage/innobase/handler/ha_innodb.cc is owned by Innobase and should not be updated.
File storage/innobase/ibuf/ibuf0ibuf.c is owned by Innobase and should not be updated.
File storage/innobase/include/row0mysql.h is owned by Innobase and should not be updated.
File storage/innobase/include/srv0srv.h is owned by Innobase and should not be updated.
File storage/innobase/include/trx0trx.h is owned by Innobase and should not be updated.
File storage/innobase/include/trx0trx.ic is owned by Innobase and should not be updated.
File storage/innobase/lock/lock0lock.c is owned by Innobase and should not be updated.
File storage/innobase/page/page0cur.c is owned by Innobase and should not be updated.
File storage/innobase/row/row0mysql.c is owned by Innobase and should not be updated.
File storage/innobase/row/row0sel.c is owned by Innobase and should not be updated.
File storage/innobase/srv/srv0srv.c is owned by Innobase and should not be updated.
File storage/innobase/trx/trx0trx.c is owned by Innobase and should not be updated.
(Set env var 'ALLOW_UPDATE_INNOBASE_OWNED' to override.)

Fix regression on pushbuild 1. The cygwin perl is ancient there, and Net::Ping does not have port_number method (port_number was introduced around 2007). The fix is to check if port_number is present. Otherwise, fallback to the slow connect().

                               table corruption

Disabling the mysiam_debug.test in embedded mode because of BUG#43733

This patch adds corrections to the original patch
submitted 2009-04-08 (http://lists.mysql.com/commits/71607):

- fixed that the original patch didn't work because of an
  incorrect condition;
- added a test case.

my_error() was invoked in reset_slave()'s with purge_relay_logs()-failing branch
without passing sql_errno to it.

Fixed with setting sql_errno= ER_RELAY_LOG_FAIL in the purge_relay_logs()-failing branch.

start-dirty would remove stored procs etc.
Skip the copying back from stored system dir if using --start-dirty

into actual tree

                                    table corruption


Moved the testcase from the file myisam.test to the new testfile 
mysiam_debug.test
 

This is a "null" merge because the fix is
already in 5.1

Error happens because sp_head::MULTI_RESULTS is not set for SP
which has 'show table status' command.
The fix is to add a SQLCOM_SHOW_TABLE_STATUS case into
sp_get_flags_for_command() func.

per-file comments:
  tests/mysql_client_test.c
the test for bug 37956 isn't relevant anymore.
The query there 'select point(?,?)' doesn't produce an error.

                       
Killing the insert-select statement corrupts the MyISAM table only
when the destination table is empty and when it has indexes. When 
we bulk insert huge data and if the destination table is empty we 
disable the indexes for fast inserts, data is then inserted and 
indexes are re-enabled after bulk_insert operation
                        
Killing the query, aborts the repair table operation during enable
indexes phase leading to table corruption.
                      
We now truncate the table when we detect that enable indexes is
killed for bulk insert query.As we have an empty table before the 
operation, we can fix by truncating the table.

MTR would die as soon as one server terminates
Implemented --wait-all option and associated subroutine

      
A bug in the initialization of key segment information made it point
to the wrong bit, since a bit index was used when its int value
was needed. This lead to misinterpretation of bit columns
read from MyISAM record format when a NULL bit pushed them over
a byte boundary.
Fixed by using the int value of the bit instead.

key_buffer_size.

The cause of corruption was number overflow when multiplying 
two ulong values, number of used keycache blocks with size
of a single block. The result of multiplication exceeded ulong 
range (4G) and this lead to incorrectly calculated  buffer offset
in the key cache.

The fix is to use size_t for multiplication result.

This patch also fixes pointless cast in safemalloc 
(size of allocated block to uint), that creates lot of false
alarm warnings when using big keycache (> 4GB) in debug mode.