Interesting project. We have a similar set of various cross-platform helpers for various C structures and tasks during all these years within Rizin - RzUtil[1][2]. They are more tightly coupled with each other though and is LGPLv3-licensed.

[1] https://github.com/rizinorg/rizin/tree/dev/librz/util

[2] https://github.com/rizinorg/rizin/tree/dev/librz/include/rz_...