> [T]hey keep adding features to C, such as type inference [...].
The thing about typeof (and its close cousin auto) is that it exposes information that the compiler’s frontend has to know anyway for type checking. That’s why GCC has had typeof for many years, even back when it only spoke pure C. So while it’s a new feature, it doesn’t really have a lot of implications for the rest of the language.
As far as ISO is concerned, each edition of the C standard is made obsolete by its successor, but that doesn't impose any obligation on you or on compiler writers. If you have gcc, you can still use `gcc -std=c90 -pedantic-errors` (or c99, or c11, or ...).
They could call the language "Stone", and then we'd get to say "such and such program is written in Stone", "not written in Stone", etc.
If they keep adding features to C, such as type inference, won't C just ultimately become as feature-laden as C++, albeit on a much longer timescale?
What's the point of that?