Avoid using gcc extensions

[cuwittrock]

Suggest to avoid using gcc extensions. The library doesn't compile for stm32c071 without enabling gcc extensions and there is no need for using gcc extensions.

[hathach]

please be specific with your setup, and compile log.

[cuwittrock]

Sorry about that - I misread the compile log. It was not tinyusb code that failed, it was something else. Your code does compile fine without extensions

[cuwittrock]

Closing thread as it was a mistake

[cuwittrock]

My bad - code does compile without extensions enabled