Added basic per-thread time zone functionality (based on public
domain elsie-code). Now user can select current time zone
(from the list of time zones described in system tables).
All NOW-like functions honor this time zone, values of TIMESTAMP
type are interpreted as values in this time zone, so now
our TIMESTAMP type behaves similar to Oracle's TIMESTAMP WITH
LOCAL TIME ZONE (or proper PostgresSQL type).
WL#1266 "CONVERT_TZ() - basic time with time zone conversion
function".
Fixed problems described in Bug #2336 (Different number of warnings
when inserting bad datetime as string or as number). This required
reworking of datetime realted warning hadling (they now generated
at Field object level not in conversion functions).
Optimization: Now Field class descendants use table->in_use member
instead of current_thd macro.
Moved all range checks for TIMESTAMP value to my_gmt_sec().
Also fixed check of upper boundary of TIMESTAMP range (which
also now will catch datetime values which are too small for
TIMESTAMP in case if time_t is unsigned).
Fixed problem with char > 128 in QUOTE() function. (Bug #1868)
Disable creation of symlinks if my_disable_symlink is set
Fixed searching of TEXT with end space. (Bug #1651)
Fixed caching bug in multi-table-update where same table was used twice. (Bug #1711)
Fixed problem with UNIX_TIMESTAMP() for timestamps close to 0. (Bug #1998)
Fixed timestamp.test
Fixed problem with localtime -> gmt where some times resulted in
different (but correct) timestamps. Now MySQL should use the smallest
possible timestamp value in this case. (Bug 316)
