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

into mysql.com:/home/psergey/mysql-4.1-nov08-push

into mysql.com:/home/psergey/mysql-4.1-nov08-push

into  mysql.com:/home/cps/mysql/trees/mysql-4.1

when calculating table->null_fields.

  Always use bundled zlib

into  ua141d10.elisa.omakaista.fi:/home/my/bk/mysql-4.1

into mysql.com:/home/hf/work/mysql-4.1.14183

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

into mysql.com:/data0/mysqldev/lenz/mysql-4.1

into moonbone.local:/work/14186-bug-4.1-mysql

Removed wrong fix for bug #14009 (use of abs() on null value causes problems with filesort)
Mark that add_time(), time_diff() and str_to_date() can return null values

into  mysql.com:/usr/home/ram/work/mysql-4.1

even when --ledir option is specified. (Bug #13774)

get real results after all checks.
(see bug #14254: func_crypt.test fails on FreeBSD with --ps-protocol).

into deer.(none):/home/hf/work/mysql-4.1.12839

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

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

into  krsna.patg.net:/home/patg/mysql-build/mysql-4.1

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

do advance the source pointer over 2 bytes that specify value length.

into mysql.com:/home/psergey/mysql-4.1-bug14139

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

into  mysql.com:/home/alexi/dev/mysql-4.1-10511

 ON UPDATE CASCADE

Procedure analyse() redefines select's fields_list. setup_copy_fields() assumes
that fields_list is a part of all_fields_list. Because select have only 
3 columns and analyse() redefines it to have 10 columns, int overrun in
setup_copy_fields() occurs and server goes to almost infinite loop.

Because fields_list used not only to send data ad fields types, it's wrong 
to allow procedure redefine it. This patch separates select's fileds_list 
and procedure's one. Now if procedure is present, copy of fields_list is 
created in procedure_fields_list and it is used for sending data and fields.

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

kernel function to prevent CPU hogs.

Date field was declared as not null, thus expression 'datefield is null'
was always false. For SELECT special handling of such cases is used. 
There 'datefield is null' converted to 'datefield eq "0000-00-00"'.

In mysql_update() before creation of select added remove_eq_conds() call.
It makes some optimization of conds and in particular performs conversion
from 'is null' to 'eq'. 
Also remove_eq_conds() makes some evaluation of conds and if it founds that
conds is always false then update statement is not processed further.
All this allows to perform some update statements process faster due to
optimized conds, and not wasting resources if conds known to be false.