Comment by oraziorillo

I re-read the second part with more calm once I got back home. There were at least a couple of things I wasn't familiar with (and therefore didn't even consider), specifically FAM and variably modified types. Thanks for the pointer, I'm realizing that having written this post and reading the comments is teaching me more about C than coding the project itself, that's crazy!

I can answer about the include guards, though. I consciously added them for portability, following the same general approach that led me to handle the big-endian to little-endian conversion explicitly in examples/mnist/idx.c: even if that safeguard is not strictly necessary on most modern systems, I love the idea that this project is potentially buildable and runnable in most environments.