Fix for a small error in the merge from 4.0

  same as above
sql_lex.h:
  same as above 
sql_union.cc:
  same as aobve
sql_select.cc:
  Fixing that SQL_CALC_FOUND_ROWS work properly in UNION's in 4.1
  Plus updating some fields in THD in the proper places 
  plus fixing a wrong result

into sinisa.nasamreza.org:/mnt/work/mysql-4.1

Barkov approved it already

into mashka.mysql.fi:/home/my/mysql-4.1

Use server character set if --default-character-set is not used
Added convert_string() for more efficient alloc+character-set convert of strings

equivalent of compile-pentium-debug but with
--enable-maintainer-mode configure option
Maybe it's worth to merge compile-mentium-debug
and compile-pentium-maintainer to a single script

into sanja.is.com.ua:/home/bell/mysql/bk/work-having_resolve-4.1

into mysql.com:/home/dlenev/src/mysql-4.1-345

The above query created a field of koi8r charset, not cp1251

Change:
CREATE TABLE a (a CHAR(1) CHARACTER SET utf8) 
Length now means character length, not byte length.
The above creates a field that guarantees can store a multibyte value
1 character long. For utf8 the above creates a field that can store
3 bytes.

into mashka.mysql.fi:/home/my/mysql-4.1

into eagle.mysql.r18.ru:/home/vva/work/mysql.orig/test/mysql-4.1

into mashka.mysql.fi:/home/my/mysql-4.0

(Mostly code cleanups)

into serg.mylan:/usr/home/serg/Abk/mysql-4.0

into gcw.ath.cx:/home/greg/bk/mysql-4.0

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

into serg.mylan:/usr/home/serg/Abk/mysql-4.0