Comment by AshamedCaptain

Or rather it simply suggests you build for two versions of the major distributions of then, or the two distributions even...

Why is my entire argument so hard to understand? To build for a different glibc you do not have to do _any_ type of arcane magic or whatever you claim. You just build in a different system... or chroot... I have been doing that _myself_ for at least 15 years, and I know of other Linux desktop commercial shops that have been doing it for much, much longer. Chroots are _trivial_.