* my_getsystime() is only an interval timer. Its value can beused for calculating
  time intervals.
* renamed my_getsystime() to my_interval_timer(), to make the semantics
  clearer and let the compiler catch wrong usages of my_getsystime()
  (also future ones, that may come in merges).
* increased its granularity from 100ns to 1ns, old value was for UUID,
  but as UUID can no longer use it directly there is no need to downgrade
  the OS provided value
* fixed the UUID code to anchor the my_interval_timer() on the epoch, as
  required by the UUID standard. That is, this was only needed by UUID,
  and now I've moved it to UUID code from my_getsystime().
* fixed other wrong usages of my_getsystime() - e.g. in calculating
  times for pthread_cond_timedwait. It was buggy and could've caused
  long waits if OS clock would be changed.

include/my_time.h:
  remove duplicate defines.
  cast to ulonglong to avoid overflow
sql/field.cc:
  perform sign extension when reading packed TIME values
sql/item_cmpfunc.cc:
  when converting a string to a date for the purpose of comparing it with another date,
  we should ignore strict sql mode.
sql/item_timefunc.cc:
  better error message
sql/item_timefunc.h:
  limit decimals appropriately
sql/share/errmsg.txt:
  don't refer to an object as a "column" in error messages that are used not only for columns.

Prior to this patch it returned microseconds since 1 Jan 1601 (Windows epoch)

implement Item_cache_int::getdate() and Item_cache_int::save_in_field()
that handle the case of the cached packed datetime value.

rewrite get_innobase_type_from_mysql_type() to use types as reported
by the Field objects, instead of relying on ad-hoc assumptions.

certain values of X.

- Fixes for type-conversion
  (time_t   is not interchangeable  with  my_time_t on Windows as time_t s 64 bit while my_time_t is long)
- BIGENDIAN-> ARCH_BIGENDIAN . 
  BIGENDIAN constant  is defined in winsock2.h (as 0)
- added explicit cast for longlong->double conversion in sql/item.h  (fixed many warnings) 

Also, HAVE_SNPRINTF is now defined and snprintf is defined to _snprintf in config-win.h

fix a typo in the boundary test.
simplify make_truncated_value_warning call.

fix a typo in the boundary test.
simplify make_truncated_value_warning call.

lp:737496 Assertion `(was_cut & 1) == 0' failed in Field_temporal::store_TIME_with_warning() in 5.1-micro

fix incorrect assert

fix the return value of Item_func_coalesce::get_date()

implement Item_func_min_max::get_date()

better default for Field::cast_to_int_type()

respect fuzzydate flags in Item_*::get_date() methods

and a different fix for lp:736370

cache temporal expression in Item_cache_int, not in Item_string.
invoke get_datetime_value() to create a correct Item_cache_int.
Implement Item_cache_int::clone, as it's a proper constant

Implement Item_func_coalesce::get_date()

lp:736370 Datetime functions in subquery context cause wrong result and bogus warnings in mysql-5.1-micro

Don't cache temporal value in an Item_string, it is compared differently.

and a test case for lp:736370 Datetime functions in subquery context cause wrong result

  Use dedicated  do_field_temporal() for Copy_field.
* check_time_range() needs to know TIME's precision to use the
  correct max value.

partial fix

Two problems:
* Item_func_convert_tz() did not tell args[0] that it needs
  TIME_NO_ZERO_IN_DATE result
* Item_func_timediff did not respect fuzzy_date limitations,
  truncated seconds when casting to signed long, resulting in
  invalid time value (hours, seconds = (uint)-1).

add missing size_of() methods to new Field* classes

issue a warning when a datetime is truncated for storing in a TIME column.
this automatically prevents optimizer from using indexes when comparing time column to a datetime

many changes:
* NOT_FIXED_DEC now create hires fields, not old ones.
  As a result, temp tables preserve microseconds (on DISTINCT, GROUP BY)
* I_S tables force decimals=0 on temporal types (backward compatibility)
* Item_func_coalesce calculates decimals for temporal types
* no precision for TIME/DATETIME in CAST means 0, not NOT_FIXED_DEC
* addtime/timediff calculate decimals from arguments (not NOT_FIXED_DEC)

sql/field.h:
  NOT_FIXED_DEC now create hires fields, not old ones
sql/item.h:
  force decimals=0 for I_S tables
sql/item_cmpfunc.cc:
  Item_func_coalesce calculates decimals for temporal types
sql/item_create.cc:
  no precision for TIME/DATETIME in CAST means 0, not NOT_FIXED_DEC
sql/item_timefunc.cc:
  addtime calculates decimals from arguments (not NOT_FIXED_DEC)
sql/item_timefunc.h:
  timediff calculates decimals from arguments (not NOT_FIXED_DEC)

Item_func_last_day did not set mayby_null=1

mysql-test/t/func_time.test:
  fixed wrong test case
sql-common/my_time.c:
  negative datetime is invalid.
  fix check_date() to reflect that.

sql/field.cc:
  initialize ltime completely
sql/filesort.cc:
  don't pack MYSQL_TIME if it's not initialized
  (safe here, but valgrind complains)
sql/item_cmpfunc.cc:
  don't pack MYSQL_TIME if it's not initialized
  (safe here, but valgrind complains)
sql/item_timefunc.cc:
  don't check MYSQL_TIME members if it's uninitialized
  (safe here, but valgrind complains)
sql/time.cc:
  use c_ptr_safe() instead of c_ptr()
  (make valgrind happy)

correct the return value of Item_func_maketime::get_date()

         and collateral changes.

* introduce my_hrtime_t, my_timediff_t, and conversion macros
* inroduce TIME_RESULT, but it can only be returned from Item::cmp_type(),
  never from Item::result_type()
* pack_time/unpack_time function for "packed" representation of
  MYSQL_TIME in a longlong that can be compared
* ADDTIME()/SUBTIME()/+- INTERVAL now work with TIME values
* numbers aren't quoted in EXPLAIN EXTENDED
* new column I_S.COLUMNS.DATETIME_PRECISION
* date/time values are compares to anything as date/time, not as strings or numbers.
* old timestamp(X) is no longer supported
* MYSQL_TIME to string conversion functions take precision as an argument
* unified the warnings from Field_timestamp/datetime/time/date/newdate store methods
* Field_timestamp_hires, Field_datetime_hires, Field_time_hires
* Field_temporal
* Lazy_string class to pass a value (string, number, time) polymorphically down the stack
* make_truncated_value_warning and Field::set_datetime_warning use Lazy_string as an argument, removed char*/int/double variants
* removed Field::can_be_compared_as_longlong(). Use Field::cmp_type() == INT_RESULT instead
* introduced Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
* in many cases date/time types are treated like other types, not as special cases
* greatly simplified Arg_comparator (regarding date/time/year code)
* SEC_TO_TIME is real function, not integer.
* microsecond precision in NOW, CURTIME, etc
* Item_temporal. All items derived from it only provide get_date, but no val* methods
* replication of NOW(6)
* Protocol::store(time) now takes the precision as an argument
* @@TIMESTAMP is a double

client/mysqlbinlog.cc:
  remove unneded casts
include/my_sys.h:
  introduce my_hrtime_t, my_timediff_t, and conversion macros
include/my_time.h:
  pack_time/unpack_time, etc.
  convenience functions to work with MYSQL_TIME::second_part
libmysql/libmysql.c:
  str_to_time() is gone. str_to_datetime() does it now.
  my_TIME_to_str() takes the precision as an argument
mysql-test/include/ps_conv.inc:
  time is not equal to datetime anymore
mysql-test/r/distinct.result:
  a test for an old MySQL bug
mysql-test/r/explain.result:
  numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/func_default.result:
  numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/func_sapdb.result:
  when decimals=NOT_FIXED_DEC it means "not fixed" indeed
mysql-test/r/func_test.result:
  numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/func_time.result:
  ADDTIME()/SUBTIME()/+- INTERVAL now work with TIME values
mysql-test/r/having.result:
  numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/information_schema.result:
  new column I_S.COLUMNS.DATETIME_PRECISION
mysql-test/r/join_outer.result:
  numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/metadata.result:
  TIMESTAMP no longer has zerofill flag
mysql-test/r/range.result:
  invalid datetime is not compared with as a string
mysql-test/r/select.result:
  NO_ZERO_IN_DATE, etc only affect storage - according to the manual
  numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/subselect.result:
  numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/sysdate_is_now.result:
  when decimals=NOT_FIXED_DEC it means "not fixed" indeed
mysql-test/r/type_blob.result:
  TIMESTAMP(N) is not deprecated
mysql-test/r/type_timestamp.result:
  old TIMESTAMP(X) semantics is not supported anymore
mysql-test/r/union.result:
  numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/r/varbinary.result:
  numbers aren't quoted in EXPLAIN EXTENDED
mysql-test/t/distinct.test:
  test for an old MySQL bug
mysql-test/t/func_time.test:
  +- INTERVAL now works with TIME values
mysql-test/t/select.test:
  typo
mysql-test/t/subselect.test:
  only one error per statement, please
mysql-test/t/system_mysql_db_fix40123.test:
  old timestamp(X) is no longer supported
mysql-test/t/system_mysql_db_fix50030.test:
  old timestamp(X) is no longer supported
mysql-test/t/system_mysql_db_fix50117.test:
  old timestamp(X) is no longer supported
mysql-test/t/type_blob.test:
  old timestamp(X) is no longer supported
mysql-test/t/type_timestamp.test:
  old timestamp(X) is no longer supported
mysys/my_getsystime.c:
  functions to get the time with microsecond precision
mysys/my_init.c:
  move the my_getsystime.c initialization code to my_getsystime.c
mysys/my_static.c:
  no need to make these variables extern
mysys/my_static.h:
  no need to make these variables extern
scripts/mysql_system_tables.sql:
  old timestamp(X) is no longer supported
scripts/mysql_system_tables_fix.sql:
  old timestamp(X) is no longer supported
scripts/mysqlhotcopy.sh:
  old timestamp(X) is no longer supported
sql-common/my_time.c:
  * call str_to_time from str_to_datetime, as appropriate
  * date/time to string conversions take precision as an argument
  * number_to_time()
  * TIME_to_double()
  * pack_time() and unpack_time()
sql/event_data_objects.cc:
  cast is not needed
  my_datetime_to_str() takes precision as an argument
sql/event_db_repository.cc:
  avoid dangerous downcast (because the pointer is
  not always Field_timestamp, see events_1.test)
sql/event_queue.cc:
  avoid silly double-work for cond_wait
  (having an endpoint of wait, subtract the current time to get the timeout,
  and use set_timespec() macro to fill in struct timespec, by adding the current
  time to the timeout)
sql/field.cc:
  * remove virtual Field::get_time(), everyone should use only Field::get_date()
  * remove lots of #ifdef WORDS_BIGENDIAN
  * unified the warnings from Field_timestamp/datetime/time/date/newdate store methods
  * Field_timestamp_hires, Field_datetime_hires, Field_time_hires
  * Field_temporal
  * make_truncated_value_warning and Field::set_datetime_warning use Lazy_string as an argument, removed char*/int/double variants
sql/field.h:
  * remove virtual Field::get_time(), everyone should use only Field::get_date()
  * remove lots of #ifdef WORDS_BIGENDIAN
  * unified the warnings from Field_timestamp/datetime/time/date/newdate store methods
  * Field_timestamp_hires, Field_datetime_hires, Field_time_hires
  * Field_temporal
  * make_truncated_value_warning and Field::set_datetime_warning use Lazy_string as an argument, removed char*/int/double variants
  * removed Field::can_be_compared_as_longlong(). Use Field::cmp_type() == INT_RESULT instead
sql/filesort.cc:
  TIME_RESULT, cmp_time()
sql/item.cc:
  * numbers aren't quoted in EXPLAIN EXTENDED
  * Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
  * virtual Item::get_time() is gone
  * Item_param::field_type() is set correctly
  * Item_datetime, for a datetime constant
  * time to anything is compared as a time
  * Item_cache::print() prints the value is available
  * bug fixed in Item_cache_int::val_str()
sql/item.h:
  * Item::print_value(), to be used from Item_xxx::print() when needed
  * Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
  * virtual Item::get_time() is gone
  * Item_datetime, for a datetime constant
  * better default for cast_to_int_type()
  * Item_cache objects now *always* have the field_type() set
sql/item_cmpfunc.cc:
  * get_year_value, get_time_value are gone. get_datetime_value does it all
  * get_value_a_func, get_value_b_func are gone
  * can_compare_as_dates() is gone too, TIME_RESULT is used instead
  * cmp_type() instead or result_type() when doing a comparison
  * compare_datetime and compate_e_datetime in the comparator_matrix, is_nulls_eq is gone
  * Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
sql/item_cmpfunc.h:
  greatly simplified Arg_comparator
sql/item_create.cc:
  * fix a bug in error messages in CAST
sql/item_func.cc:
  Item::cmp_result() instead of Item::is_datetime() and Item::result_as_longlong()
  mention all possibitiles in switch over Item_result values, or use default:
sql/item_row.h:
  overwrite the default cmp_type() for Item_row,
  as no MYSQL_TYPE_xxx value corresponds to ROW_RESULT
sql/item_timefunc.cc:
  rewrite make_datetime to support precision argument
  SEC_TO_TIME is real function, not integer.
  many functions that returned temporal values had duplicate code in val_* methods,
  some of them did not have get_date() which resulted in unnecessary date->str->date conversions. 
  Now they all are derived from Item_temporal_func and *only* provide get_date, not val* methods.
  many fixes to set decimals (datetime precision) correctly.
sql/item_timefunc.h:
  SEC_TO_TIME is real function, not integer.
  many functions that returned temporal values had duplicate code in val_* methods,
  some of them did not have get_date() which resulted in unnecessary date->str->date conversions. 
  Now they all are derived from Item_temporal_func and *only* provide get_date, not val* methods.
  many fixes to set decimals (datetime precision) correctly.
sql/log_event.cc:
  replication of NOW(6)
sql/log_event.h:
  replication of NOW(6)
sql/mysql_priv.h:
  Lazy_string class to pass a value (string, number, time) polymorphically down the stack.
  make_truncated_value_warning() that uses it.
sql/mysqld.cc:
  datetime in Arg_comparator::comparator_matrix
sql/opt_range.cc:
  cleanup: don't disable warnings before calling save_in_field_no_warnings()
sql/protocol.cc:
  Protocol::store(time) now takes the precision as an argument
sql/protocol.h:
  Protocol::store(time) now takes the precision as an argument
sql/rpl_rli.cc:
  small cleanup
sql/set_var.cc:
  SET TIMESTAMP=double
sql/set_var.h:
  @@TIMESTAMP is a double
sql/share/errmsg.txt:
  precision and scale are unsigned
sql/slave.cc:
  replication of NOW(6)
sql/sp_head.cc:
  cleanup
sql/sql_class.cc:
  support for NOW(6)
sql/sql_class.h:
  support for NOW(6)
sql/sql_insert.cc:
  support for NOW(6)
sql/sql_select.cc:
  use item->cmp_type().
  move a comment where it belongs
sql/sql_show.cc:
  new column I_S.COLUMNS.DATETIME_PRECISION
sql/sql_yacc.yy:
  TIME(X), DATETIME(X), cast, NOW(X), CURTIME(X), etc
sql/time.cc:
  fix date_add_interval() to support MYSQL_TIMESTAMP_TIME argument
storage/myisam/ha_myisam.cc:
  TIMESTAMP no longer carries ZEROFIELD flag, still we keep MYI file compatible.
strings/my_vsnprintf.c:
  warnings
tests/mysql_client_test.c:
  old timestamp(X) does not work anymore
  datetime is no longer equal to time