What does HackerNews think of zephyr?
Primary Git Repository for the Zephyr Project. Zephyr is a new generation, scalable, optimized, secure RTOS for multiple hardware architectures.
This would probably be a good time to mention https://github.com/zephyrproject-rtos/zephyr.
It's quite easy to set up and writing drivers for it isn't really so much of a pain. I don't know if one should state it as a pain point or a good point but they do use CMake for the build system. So it's reasonably quick at least they are using a newer version of CMake than most projects I've had the joy of testing out.
Their APIs are quite linux/posix inspired in my opinion but with their own zephyr flavor on top. But I would say NuttX is probably a more mature project and Zephyr has been reworked quite heavily lately so a lot has changed but at least they'll have an LTS release soon.