Add wasmi::Linker::func_wrap method

[Robbepop]

This allows to define host functions for a Linker without the need to associate them to a Store and enable cross-store sharing of those host functions.

This feature request came up first in #657 (comment). Note the explanation of Linker::define confusion: #657 (comment)

cc @flavio

[flavio]

I looked into the WIP code I had, there's still a lot to be done and I doubt I would be able to get this done quickly. Hence, you can work on this issue @Robbepop.

Once this API is released I'll update my wit-bindgen fork to make use of it.

Thanks!

[Robbepop]

Okay, will work on it soon(TM).

Looking forward to the wit-bindgen update! :)
Any chance your work on wit-bindgen might be merged into mainline?

[flavio]

Okay, will work on it soon(TM).

Thanks, no hurries!

Any chance your work on wit-bindgen might be merged into mainline?

I doubt, from my understanding they want to split the current implementation into modular blocks that would allow everybody to write their own wit-bindgent. I think the end goal could be to have my code into a dedicated repository, which would no longer be a fork.

However, thinks are moving really fast and everything keeps breaking in between each iteration.