Rust has a complete #nostd mode where most of it's ergonomics are still usable without any runtime. It also supports pluggable allocators, as well as replacing most of the builtin functionality of other language components (lang items).
It's story around panic and debug handling is also improving, including cutting out formatting code for things like println! and debug! when targetting embedded platforms.
but not necessarily posix/windows/etc
having C as a least-common-denominator toolchain which almost all platforms will provide is still useful for the embedded world where sqlite has a huge number of applications..