Hello rustaceans, I'm trying to write a lib crate for embedded, I have a question about configuration. The following is what I want to do:

- use .toml as the configuration file, library users could customize their own config when using the library
- provide lib users a `build.rs` to load user's .toml file and generate consts of all configurations at compile-time
- all config structs are defined in library with defaults, only defined config are loaded from toml

I tried `const-gen` crate, but it cannot generate structs from library. `proc-macro` seems not feasible for this case as well. Is there any other solutions for it?