Support for operating system facilities in no way implies those facilities are necessary.
> filesystem, dynamic memory allocation, threads
All of which can be (and has been) done without an OS. Besides, there is no native C language support for any of those things. Those things are usually (but certainly not always) done by library calls, not language primitives.
My underlying point is that the premise of the question is mistaken. It's assuming that an operating system is required in order to have a programming language. That is simply untrue, and is particularly untrue for C, which is very commonly used to program microcontrollers that have no operating system. I'm working on one such system right now.
> filesystem, dynamic memory allocation, threads
All of which can be (and has been) done without an OS. Besides, there is no native C language support for any of those things. Those things are usually (but certainly not always) done by library calls, not language primitives.
My underlying point is that the premise of the question is mistaken. It's assuming that an operating system is required in order to have a programming language. That is simply untrue, and is particularly untrue for C, which is very commonly used to program microcontrollers that have no operating system. I'm working on one such system right now.