author here. My RTOS of choice (ChibiOS) uses a lot of function like macros which are not supported by rustbindgen. Other RTOSes such as FreeRTOS or UC/OS-II would be easier but they don't provide drivers, making them less interesting.
If anybody has experience with writing C macros to rust bindings I would be interested in hearing about it.
I know that chibi OS is funded by ST(for developing a version for their automotive line of automotive mcu's). Hence why it's only limited to ST platforms(still that's a lot of variety at great price).
Maybe they'll be interested in funding rust development? it might give them some competitive advantage, some amount of control of a possible future platform, i.e. rust.
If anybody has experience with writing C macros to rust bindings I would be interested in hearing about it.