Problem #1: INSERT...SELECT, Version for 4.1.
INSERT ... SELECT with the same table on both sides (hidden
below a MERGE table) does now work by buffering the select result.
The duplicate detection works now after open_and_lock_tables() 
on the locks.
I did not find a test case that failed without the change in
sql_update.cc. I made the change anyway as it should in theory
fix a possible MERGE table problem with multi-table update.

(Backport of an identical change from 5.0)

into  a193-229-222-105.elisa-laajakaista.fi:/home/my/bk/mysql-4.1

into moonbone.local:/work/15028-bug-4.1-mysql

depending on table order

multi_update::send_data() was counting updates, not updated rows. Thus if one 
record have several updates it will be counted several times in 'rows matched'
but updated only once.

multi_update::send_data() now counts only unique rows.

to be in the query cache. (BUG#14652)

into  mysql.com:/home/jimw/my/mysql-4.1-clean

into  a193-229-222-105.elisa-laajakaista.fi:/home/my/bk/mysql-4.0

into mysql.com:/home/gluh/MySQL/Merge/4.1

  added SSL_library_init()

into  mysql.com:/usr/home/bar/mysql-4.1.b10446

into  mysql.com:/usr/local/mysql/mysql-4.1

into  mysql.com:/usr/home/bar/mysql-4.1.b14406

into  mysql.com:/usr/home/bar/mysql-4.1.b14406

into mysql.com:/Users/kent/mysql/bk/mysql-4.1

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

CREATE TABLE and PS/SP": make sure that 'typelib' object for
ENUM values and 'Item_string' object for DEFAULT clause are 
created in the statement memory root.

into  mysql.com:/usr/local/home/marty/MySQL/mysql-4.1

into moonbone.local:/work/14482-bug-4.1-mysql

crash

resolve_const_item() substitutes item which will evaluate to constant with
equvalent constant item, basing on the item's result type. In this case
subselect was resolved as constant, and resolve_const_item() was substituting
it's result's Item_caches to Item_null. Later Item_cache's function was called
for Item_null object, which caused server crash.

resolve_const_item() now substitutes constants for items with 
result_type == ROW_RESULT only for Item_rows.

into  mysql.com:/usr/local/home/marty/MySQL/mysql-4.1

into mysql.com:/M41/mysql-4.1

Fix a possible problem on RPM un-install. bug#15145

into  sanja.is.com.ua:/home/bell/mysql/bk/mysql-4.0

into  a193-229-222-105.elisa-laajakaista.fi:/home/my/bk/mysql-4.0

into mysql.com:/Users/kent/mysql/bk/mysql-4.1

item_strfunc.h, item_strfunc.cc, item.cc:
  Try to convert a const item into destination 
  character set. If conversion happens without
  data loss, then cache the converted value
  and return it during val_str().
  Otherwise, if conversion loses data, return
  Illeral mix of collations error, as it happened
  previously.
ctype_recoding.result, ctype_recoding.test:
  Fixing tests accordingly.

into  neptunus.(none):/home/msvensson/mysql/mysql-4.1

into  neptunus.(none):/home/msvensson/mysql/mysql-4.1

 - Backport from 5.0