These asserts throw on darwin, before `meta.platforms` is checked. This, among many others, makes CI require ugly workarounds. Upstream says its build requirements are "gcc/clang, ..." - so it seems like these asserts are not required in principle. Also, they are 10 years old. Can't test, because the packge is marked as broken entirely. Tried updating to latest 2.7.1, but the build didn't succeed either.