nvi: Rename O_PATH to O_NVIPATH

[kib]

Summary

O_PATH conflicts with the open(2) option existing on both Linux and FreeBSD.

[bapt]

Have you upstreamed that?

[kib]

In D30344#681526, @bapt wrote:

Have you upstreamed that?

No and I do not have any contacts.

[bapt]

Upstream is there: https://github.com/lichray/nvi2

[kib]

In D30344#681532, @bapt wrote:

Upstream is there: https://github.com/lichray/nvi2

Thanks. Apparently upstream already has something done differently, please see f804087623a3eb9800b7bb6.
Do you plan to import any new revision?

[bapt]

I was not planning at first, as I planned to track releases, but if needed it is fine to follow snapshot. so if easier for you, I can import a snapshot now.

[kib]

In D30344#681539, @bapt wrote:

I was not planning at first, as I planned to track releases, but if needed it is fine to follow snapshot. so if easier for you, I can import a snapshot now.

It is certainly not critical, since redefine in the nvi sources for O_PATH papers over the issue. But if possible, importing something that included the referenced fix would be nice.