I am inclined to just close this because cmake changes rapidly and the problem is from 2017. i'm also sort of surprised it's possible to build cmake on a vax at all... However, I'll leave it open for the moment; if the issue is still interesting and/or anyone has any input as to whether it's still current, let me know.
It is no longer a problem. IIRC, changes by joerg@ in 2017 fixed things. Also:
http://cdn.netbsd.org/pub/pkgsrc/current/pkgsrc/devel/cmake/index.html NetBSD 9.0 vax cmake-3.25.1.tgz Thanks, John