Emmanuel Dreyfus <manu@netbsd.org> writes:

> EMUL_BSD_ASYNCIO_PIPE notes that the emulated binaries expect
> the original BSD pipe behavior for asynchronous I/O, which is
> to fire SIGIO on read() and write(). OSes without this flag do
> not expect any SIGIO to be fired on read() and write() for
> pipes, even when async I/O was requested. As far as we know,
> the OSes that need EMUL_BSD_ASYNCIO_PIPE are NetBSD, OSF/1 and
> Darwin.

I think it's at least confusing that the native emulation (NetBSD)
needs to set a flag to specify its previous behaviour.  The logic of
this seems backwards to me; I'd rather expect emulations to specify
that they do _not_ want the native behaviour.