Yes, there is a change, we’ve introduced a new package called linux-lib-rust that provides all the kernel headers and artifacts to be able to compile Rust modules. You need to install this package and your out-of-tree module should build.
The main motivation for the separate linux-lib-rust is that we didn’t want to increase the size of linux-headers unnecessary, this allows to save storage, save some energy and people that are interested to do experiments with Rust can simply install this additional package.
I was trying to modify the post, but it looks like it’s read-only now… I hope people that are interested will read this comment… 