Hi Boris, Thanks for looking into this issue with the FreeImage plugins.
Your explanation makes sense and I should have probably looked more carefully at the details of the patch when cherry-picking this from the Fedora packaging.
I'll find some time to try out your patch and roll it out with the next iteration of the package. I might also try to break the large Disabled-vendored-dependencies.patch patch into individual per-pulgin patches to help with future maintenance work.
Your work will be duly acknowledged of course. Best regards, Ghis