Build cmake 3.31.7nb2 on qemu

It was long road, at 21 h 40m at least (I think bootstrap was done
separately by pkg_rolling-replace -uv). single CPU qemu VM with 1Gb of ram,
offloading to distcc server in another qemu-system-sparc, with 1 cpu and
just 256 Mb ram (yes, I need to up memory there, but sor far it my
longest-running virtual NetBSD/sparc instance, so I keep it running)

Interesting thing, for me bootstrap cmake was unable to find c11 feature
unique_ptr and thus stopped pkg_rolling-replace from making progress!

I manually removed this fatal message from workdir/CMakeLists.txt (line 92
from memory) and cmake build itself and was packaged. This is all on 10.1's
gcc 10.5.0.

So I re-run rolling-replace, hope it will be happy with cmake now!