The installer looks for libiberty.a in /usr/local/lib/$ARCH, but homebrew has installed it for me in /usr/local/lib

This line at https://github.com/Groundworkstech/pybfd/blob/master/setup.py#L343-L344 causes the issue (which potentially fixes it on other systems so idk)

I propose this part of the code builds two versions of lib_liberty_fullpath - one with $ARCH and one without, and only fails if neither file exists.