[psi-squared]

It looks like the first part of what you want is nearly there - see https://github.com/Yamakaky/rust-bindgen

It converts C headers to a Rust module containing the relevant type/function/etc. definitions. On stable you need to either pregenerate the module (not too bad if you're pinning particular versions of libraries anyway) or add a build script to autogenerate it. On nightly, there's also a compiler plugin that does all the work for you, and looks not-too-dissimilar to what you wanted. The only thing it lacks is the prefix removal stuff.