I think more than a C backend, LLVM needs "C as an IR". Which LLVM can internally use to "trivially" add support for embedded-type platforms that only have a C compiler.
That is what most people want it for anyways.
That is what most people want it for anyways.
If C is the output of the compiler, then we speak of a C Backend, which means the part that transform the final IR in the other language we want to translate to (eg: x86, arm6, sparc, ... C :)
As a final note, it's likely that platforms so conservatives that they only provide a C ansi compiler, will not be aroused by Rust.