Add SOCK_CLOEXEC and SOCK_NONBLOCK socket flags.

SOCK_CLOEXEC is used to atomically set close-on-exec flag for the new
descriptor(s), and SOCK_NONBLOCK is used to mark descriptor(s) as
non-blocking.

Change-Id: I8ba6a70543d23759e3ddcc7ff9c21b567184d681
1 file changed