Hi guys,
My 2 cents, not related to ncurses in particular:
10+ years ago I used to work for a small Linux distribution. We built our build system from scratch. Each package was separately built in designated chroot (usually ./configure; make; make install – or whatever was required for that package), these kinds of builds were parallelized across multiple computers. It worked like a charm. We had a very few special cases (maybe 2-3 packages out of 1000) where the build was undeterministic for various weird reasons that we tracked down individually (the one I remember was that the 1 second precision of files' timestamps wasn't fine-grained enough, we needed to insert a "sleep 1.1" somewhere to make absolutely sure the timestamp increased).
At one point a colleague of mine insisted on trying "make -j2" (or -j4, can't recall – whatever) builds by default to speed them up. I firmly opposed, but we gave it a try. Out of the ~1000 packages we had we saw a failure after like perhaps the 10th package that we tried to build. That was the moment we reverted this change for good.