specifying DEFAULT

This was not specific to datetime.  When there is no default value 
for a column, and the user inserted DEFAULT, we would write 
uninitialized memory to the table.  

Now, insist on writing a default value, a zero-ish value, the same 
one that comes from inserting NULL into a not-NULL field.

(This is, at best, really strange behavior that comes from allowing 
sloppy usage, and serves as a good reason always to run one's server 
in a strict SQL mode.)

into  zippy.cornsilk.net:/home/cmiller/work/mysql/bug23411/my50-bug23411

  
The Item_func_mod objects never had maybe_null set, so users had no reason 
to expect that they can be NULL, and may therefore deduce wrong results.
Now, set maybe_null.

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

into  neptunus.(none):/home/msvensson/mysql/my50-m-stress

Use lowercase for "Too long dbname" test as it will be put ot lower on some platforms and we don't wan't to test that.

into  neptunus.(none):/home/msvensson/mysql/my50-m-stress

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

into  zippy.cornsilk.net:/home/cmiller/work/mysql/mysql-5.0-maint

into  zippy.cornsilk.net:/home/cmiller/work/mysql/mysql-4.1-maint

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

  Raise version number to 4.1.23

into  rolltop.ignatz42.dyndns.org:/mnt/storeage/mysql-5.0-maint

into  rolltop.ignatz42.dyndns.org:/mnt/storeage/mtr_vs_config/my50-mtr_vs_config

Visual Studio builds each configuration in a different sub-directory.  Only the sub-
directories for release and debug are currently searched.

into  kpdesk.mysql.com:/home/thek/dev/mysql-5.0-maint

into  kpdesk.mysql.com:/home/thek/dev/mysql-4.1-maint

- 'false' not defined in C, use FALSE instead.

- 'false' not defined in C, use FALSE instead.

into  mysql.com:/usr/home/ram/work/bug22913/my41-bug22913

into  mysql.com:/usr/home/ram/work/bug22913/my50-bug22913

into  mysql.com:/usr/home/ram/work/bug22913/my50-bug22913

We don't check for errors that may occur during data printing.

into  bodhi.local:/opt/local/work/mysql-5.0-runtime-merge

into  bodhi.local:/opt/local/work/mysql-5.0-runtime-merge

into  bodhi.local:/opt/local/work/mysql-4.1-runtime