Let's hax0r a GC… (eventually)

See Look Ma, h4x0rs! for an introduction to this series.
AKA, we h4x0r a mere (parallel) arena allocator
There’s absolutely no reason for memory management in C to be as hard as it is. In fact, there’s almost never a good reason for memory management to be hard, and is one of my issues with Rust– why should I work even harder on memory management than I would in C?