framework to verify binary compatibility

In the 4.2.0 release we ran into binary incompatibilities late in the release cycle that ended up costly to fix. What would have prevented the incompatibilities, or at least allowed us to detect them early on, would have been an automated framework to verify the binary compatibility of the library. This is a placeholder issue to design and implement such a framework.

I'm guesstimating the effort of putting something like this in place at 80 hours, possibly more.