I'd expect something like a super-C that provides a counted-byte string (still NUL-terminated for interoperability) type and support functions, `defer` or similar, `with`-like macros, etc., `mutable`/`immutable`. Such a thing could be like C++ was in the beginning: a front-end that translates to C99 or whatever standard is your lowest common denominator. You'd still have to do manual memory management, so you'd still have use-after-free issues, but they'd be a lot less common. Similarly you'd still have races, but a lot fewer.
