I have a library released under a license incompatible with the GPL. That library adds some critical feature to the GPL program that I want to modify. And I also want to make the result available to the public, but without releasing the source of the resulting executable (only the original one).
What I have in mind right now is releasing a binary patch to the executable compiled from the legit GPL source. Say, I compile the original GPL code to exe, then I compile the modified one, that adds my incompatible library's functionality, then I do binary diff and only release the file that contains bytes that should be written to the original exe, and where one should put them.
Such a patch doesn't have a single piece of code that the original GPL program has, so it's not a derivative work. It isn't designed to work along with that program either. It just changes some bytes, and it's hard to tell what those bytes do, what they internally are, and what's the source of the library that was added.
Does this approach get covered anywhere in the official docs about GPL?