Ah, well even if it's some super-obscure or internal thing, if it compiles down to C that doesn't mind POSIX you might still be able to Emscripten-ify it!

(Part of my thinking with this solution is to broadcast "you are asking me to do something that requires a solution this complex to wrangle the problem space effectively" to try to fend off similar inanity in the future, admittedly, perhaps I'm being a bit optimistic/unrealistic heh.)