Typedef support

[TimWhiting]

Now that Dart 2.13 has non-function typedef support I think it would be reasonable to translate C typedefs to Dart typedefs. In a library I'm attempting to wrap it has a lot of simple typedefs, which makes it hard when I'm trying to find some type under a certain name as specified in the headers, only to find it has a different name in the dart library generated by ffigen.

[mannprerak2]

Yes, this would be a good feature, especially when structs have multiple names. We should still probably only generate typedefs that are being used somewhere in the generated code.

[TimWhiting]

I think that only generating typedefs that are being used somewhere is a good default, but the option to include all typedefs should be available.

[mannprerak2]

From what I see, having typedefs that aren't being used anywhere in the generated bindings would be useless, even if generated.

Can you point out some use cases for when this would be helpful? Otherwise simply generating only the required typedefs would be much simpler.

[TimWhiting]

I guess you are right. I can't think of a situation where that would be useful