Fixes:

- Bug #26662: mysqld assertion when creating temporary (InnoDB) table on a tmpfs filesystem
  Fix by not open(2)ing with O_DIRECT but rather calling fcntl(2) to set
  this flag immediately after open(2)ing. This way an error caused by
  O_DIRECT not being supported can easily be ignored.
- Bug #23313: AUTO_INCREMENT=# not reported back for InnoDB tables
- Bug #21404: AUTO_INCREMENT value reset when Adding FKEY (or ALTER?)
  Report the current value of the AUTO_INCREMENT counter to MySQL.