I agree with what I think Marc is suggesting, that we can get a good solution
here without accounting for all (or perhaps any) memory leaks.
The Julia project doesn't really care about memory leaks in this context anyway.
Here's a comment by one of the language designers, Stefan Karpinski
Hi Niels,
This sounds hopeful!
> To make any progress with adding a callback like this, we'd need to
> either:
>
> 1. Find out and document how to longjmp out from the callback safely.
>
> 2. Agree and document that when GMP invokes this callback, GMP state
> should be considered invalid. The
