gargantua

There are currently no examples in [example_code/](https://github.com/ccgargantua/arena-allocator/tree/main/code_examples) that showcase the use of the [arena_expand](https://github.com/ccgargantua/arena-allocator/blob/0a2addbccd8d2e44e3e84a5f972e1a4151addd9c/arena.h#L126) and [arena_copy](https://github.com/ccgargantua/arena-allocator/blob/0a2addbccd8d2e44e3e84a5f972e1a4151addd9c/arena.h#L191) functions. These would be beneficial to add.

The [arena_expand()](https://github.com/ccgargantua/arena-allocator/blob/81e055eaebe8b33f8083f4b47a225534a10ce5d1/arena.h#L308) function relies on implementation for deallocation As for as I can tell: deallocation of the `ptr` argument for `realloc` ([the default `realloc` for ARENA_REALLOC](https://github.com/ccgargantua/arena-allocator/blob/81e055eaebe8b33f8083f4b47a225534a10ce5d1/arena.h#L262)) is not officially guaranteed...

The current `Makefile` only functions as intended on Linux, but not Windows. Here is a description of problems and potential solutions. 1. Valgrind is not supported on Windows. Since PRs...

I happened to notice that [this](https://github.com/slembcke/Chipmunk2D/blob/d0239ef4599b3688a5a336373f7d0a68426414ba/src/prime.h#L24) URL to planetmath.org happened to be broken. I'm sure I'm the only one to have tried this in the last decade and will probably...

I would like to contribute to RKTest, and saw that it uses `pytest` and snapshot tests. I'm familiar with Python and with the concept of snapshot tests, but not pytest...