Yes, with ELF's shared library stuff you can have several versions of a library installed side by side, systemwide, as long as they advertise their ABIs are different.
But the trouble is that application A uses a hacked version of library L, while application B uses another hack on the same base version of L. Both versions of L are "almost" compatible... but not interchangeable.
Decent solution: Don't hack L, fix the application. If an extension is required, pack that as a separate library. If a fix is warranted, push it upstream and require a new enough version of the library. This being FLOSS, everybody is free to get the extension or the fixed version. If none of the above works, fork (but commit to maintaining said fork and/or merge with upstream later on).
Copyright © 2017, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds