On Mac Lion, installing a fresh MacPorts from scratch, then calling
port -N mpkg lilypond-devel +mactex +perl5_28 +python37 always causes a (harmless) abort. The reason is that `libunwind-headers' gets installed as part of the dependencies rather early, but one of the very last steps is installation of `libgcc9', which doesn't work with activated `libunwind-headers'. Is it possible to somehow tell `port' in the above command that `libunwind-headers' has to be deactivated before building `libgcc9'? Werner