Rust has libcore, which is, in many ways, more featureful than libc despite also having zero dependencies. From my perspective, the main advantage of C is the way in which chip manufacturers only provide (poorly supported/bug-ridden) C compilers, but this is likely to become less important as ARM takes over more and more of the world: it is only getting easier and cheaper to throw a full ARM chip into a device, due to economies of scale.