erl_child_setup is linked together with hash.o so we need to
inline any functions into it when running in debug mode.

The functions io:columns() and io:rows() only worked correctly inside
interactive erlang shells before this fix. These functions returned
{error,enotsup} before this fix even if stdout and stdin were
connected to a terminal when they were invoked from an escript or a
program started with e.g., `erl -noshell`.

This commit fixes issue ERL-717.

The poll code for kevent on OpenBSD and NetBSD had not been fixed
to work properly when disabling events in the scheduler poll-set.
Because they use ONESHOT the delete operation was built into the
trigger and thus a lot of code was not needed when doing oneshot,
however it is needed when doing non-oneshot.

Incorrect precidence rules made the driver never
deselect the given fds.