I'm thinking exit() shouldn't be catchable to maintain status quo, and it should be focused on the reason it was suggested(Unwinding stacks and cleaning up memories instead of longjmp'ing to shutdown).
If there's any need to catch it's exception, that can be handled later through maybe a RFC discussion. This can be implemented directly without having any user land interaction since the throwing and catching can't be caught by any user land code(top-most hierarchy without possibility to be caught, which might result in compile time error). All the best
