Should this use Rust ABI dylib or the C/C++ ABI cdylib

[CGMossa]

While diagnosing my initial build issues on windows, see #2 , I found this thread describing the difference between cdylib and dylib. Turned out, it wasn't an issue for me to use dylib, but this might be a problem down the line. Also, r-rust/hellorust uses cdylib.

This is specifically concerning the generated Cargo.toml file in the source.R file.

[clauswilke]

What change is needed to switch to cdylib? It sounds to me like it's the right thing to do.

[CGMossa]

It just requires changing generate_cargo.toml. I just don't know what the consequences of that is.
Maybe it entails longer compile time, or some restriction, that I'm unfamiliar with.
For instance, the hello-code in the README.md is 7.1 MB when using dylib and 5.5 MB when using cdylib.

Hopefully @dasmoth or Andy have some ideas what this decision entails.

[clauswilke]

Tagging @andy-thomason so he sees this issue.

[andy-thomason]

It seems that cdylib is intended for building C API extensions for other things that
expect it (such as R) ie. C <-> Rust.

dylib is for extending Rust frameworks and presumably allows rust functions
to call Rust functions Rust <-> Rust.

I would definitely go for cdylib as the C ABI has remained invariant for decades
apart from some minor bug fixes.

[clauswilke]

Sounds good, I'll switch to cdylib.

[clauswilke]

This is done now.