netbsd: Export ioctl request generator macros

[qinghon]

Description

add ioctl request generator macros for netbsd like

Sources

• NetBSD https://github.com/NetBSD/src/blob/trunk/sys/sys/ioccom.h
• OpenBSD https://github.com/openbsd/src/blob/master/sys/sys/ioccom.h

Checklist

• Relevant tests in libc-test/semver have been updated
• No placeholder or unstable values like *LAST or *MAX are
  included (see rust-lang/libc#3131)
• Tested locally (cd libc-test && cargo test --target mytarget);
  especially relevant for platforms that may not be checked in CI

  ci broken in netbsd

@rustbot label +stable-nominated

[rustbot]

Some changes occurred in OpenBSD module

cc @semarie

[rustbot]

Some changes occurred in OpenBSD module

cc @semarie

[semarie]

with IOC_INOUT fixed, the change is fine regarding OpenBSD.

[semarie]

LGTM.

@tgross35 I reviewed both OpenBSD and NetBSD code, and it looks fine.
But I only tested it on OpenBSD.