Linux

The article actually covers that kind of defensive work a bit (although it's all kernel internals):

"...if Rust disappeared tomorrow, we have cleaned up the C code in the kernel so much and taken in the ideas. We thank you, you've made Linux better with it just by existing."

He described new C "guards" and scoped locks inspired by Rust ...

And

Beyond language features, Kroah-Hartman tied Rust directly to a broader push around untrusted data and the idea that "all input is evil."
... He described ongoing work on an "untrusted" type wrapper and a validate method in Rust that forces explicit validation at the point where data crosses from untrusted to trusted.