These should add possible (but not guaranteed!) compatibility for packages
built against ABI-broken versions of libraries, i.e. packages where the
assemblies inside have removed methods or properties. We expect some
breakage to be reported, but it should be less annoying for users of a wide
variety of distributions not to block installation of their old packages.
Former-commit-id: b0a602b388b02324ebdab6db8aa2d3a6d6e001f0
