I just wanted to follow-up on my other post Re: Using Perlbrew macOS impossible to install distributions. The stackoverflow thread mentioned that the bug had been reported to rt.perl.org. However, I searched (using the public interface) and I did not find the relevant bug report. So, I searched around some more and it appears that this might be a bug in macOS High Sierra (10.13), see this Apple Discussion thread. It seems that the problem is still not fixed in macOS version 10.13.1 (since I still get the test failures on 10.13.1 unless I install Berkeley DB first).