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.