unix: use setattrlist for UtimesNano on Darwin for ns resolution

Follow CL 74952 for x/sys/unix.

Update golang/go#22528

Change-Id: Id146da75b80a64cfa4eac28e9bb7b3befe944718
Reviewed-on: https://go-review.googlesource.com/75610
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

unix/syscall_netbsd.go

@@ -124,6 +124,11 @@ func sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 	return -1, ENOSYS
 }
 
+func setattrlistTimes(path string, times []Timespec) error {
+	// used on Darwin for UtimesNano
+	return ENOSYS
+}
+
 /*
  * Exposed directly
  */