A timespec on netbsd/amd64 is int64/int64, not int64/int32.
This bug appears to have been introduced in 7777bac6.

Spotted by Cherry Zhang while reviewing https://go-review.googlesource.com/c/go/+/177120.

Change-Id: I163c55d926965defd981bdbfd2511de7d9d4c542
Reviewed-on: https://go-review.googlesource.com/c/go/+/177637Reviewed-by: Benny Siegert <bsiegert@gmail.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Benny Siegert <bsiegert@gmail.com>