Keep track of new Rust features for unsafe FFI code

[FreezyLemon]

1.82.0 for example. Raising MSRV to 1.82 is very aggressive as of now, but it should be kept in mind

[FreezyLemon]

For future reference: 1.83 - 1.89: various new or newly const pointer APIs

1.82 contains:

• Native syntax for creating a raw pointer: unlikely to be important for this crate
• Safe items with unsafe extern: need to see how bindgen handles this, or switch to manual bindings.rs creation?

1.80:

• add size_of and align_of to the prelude
• add a lot of NonNull functions
• check-cfg always enabled

1.77:

• C string literals

1.75:

• std::mem::zeroed is const