C FFI structs have to be marked `#[repr(C)]` to guarantee they'll be represented how C structs would be. It might be a reasonable change to implicitly allow dea

C FFI structs have to be marked `#[repr(C)]` to guarantee they'll be represented how C structs would be. It might be a reasonable change to implicitly allow dead fields on any struct with a C repr (since using the struct in C effectively makes all of its fields public).