rename O_DIRECTORY to O_TMP_DIRECTORY to avoid conflict with open option

This is a rejiggering of 07fd7151247068ce418d8a4847003369b5dbd1d2
from upstream (git://repo.or.cz/nvi.git).

Signed-off-by: Garrett Cooper <yanegomi@gmail.com>
Rename O_DIRECTORY to O_TMP_DIRECTORY

Signed-off-by: Garrett Cooper <yanegomi@gmail.com>