So... final update: I got it to work.
Apart from the changes mentioned above:
1. I changed the argument definitions in the callback (from `cstring` to
`ccstring`)
2. every time I used one of these params (`seq` and `req`) within the
callback, I cast them to `cstring`, like:
cast[cstring](seq)
Run
Now, my only issue is VCC/cl itself I guess. The linking stage takes ages to
complete (~60 minutes compared to 5-6 minutes on Linux/Mac CI builds), but I
have no idea why.
I want(ed) to use MINGW, but then the issue is that I get one ton of other
unrelated errors (because of the Webview2-related libraries) + I've seen that
it's very challenging. So, I decided to abandon the idea and go for VCC.
