MBED_CONF_RTOS_PRESENT incorrectly pass to in-tree static library or conversely

[ccli8]

MBED_CONF_RTOS_PRESENT is defined in mbed-rtos-flags. For libraries which need to distinguish between mbed-os or mbed-bardmetal build, e.g. ESP8266Interface.h, they need to determine to link mbed-rtos-flags to get in MBED_CONF_RTOS_PRESENT (for linking mbed-os) or not (for linking mbed-baremetal). But only application-level CMakeLists.txt knows which of mbed-os and mbed-baremetal is linked, and this information isn't passed to these libraries which rely on MBED_CONF_RTOS_PRESENT. This will generate such error: application linking mbed-baremetal but libraries having MBED_CONF_RTOS_PRESENT definedㄝor conversely.

One rough fix is these libraries all link mbed-core-flags and let application-level CMakeLists.txt determine to link mbed-rtos-flags additionally for these libraries. But this fix isn't compatible and isn't easy to apply.

[multiplemonomials]

One rough fix is these libraries all link mbed-core-flags and let application-level CMakeLists.txt determine to link mbed-rtos-flags additionally for these libraries. But this fix isn't compatible and isn't easy to apply.

Yeah, that's basically what I have done until now. But honestly, it's an ugly way to do it, and it can cause a lot of unexpected issues.

I've been seriously considering just making it so a given project is set to "baremetal mode" or "OS mode" and then that globally controls whether mbed-core-flags and mbed-rtos-flags are linked together or not. That would remove the ability to have some apps build with baremetal and others build with OS within a single project. But honestly, I am not sure anyone is actually using that feature.

So basically, I'd accept a PR to fix this mess by only having one of mbed-baremetal or mbed-os active at a time, set by a JSON option.

[ccli8]

That would remove the ability to have some apps build with baremetal and others build with OS within a single project. But honestly, I am not sure anyone is actually using that feature.

This feature needs two build modes at the same time for single static library, like mbed-os and mbed-baremetal. But currently these static libraries only have single build mode: either mbed-core-flags or mbed-core-flags/mbed-rtos-flags exclusively. So I think this feature can be not taken into account, except these static libraries also support two build modes simultanelusly.