Typos discovered while hamering on the repo

[pirbo]

I've done some heavy work to avoid as much as possible the use of ctypes-foreign. Not sure, it is a good idea; I'll open a PR with the result where we'll can discuss whether it makes sense. Still, in the process, I've discovered a few glitches:

• unused definitions
• duplicates
• functions SDL asks us to not use anymore
• too generic types

that, I think, would be nice to change independently of the mega rewrite of the plumbing...

[dbuenzli]

This looks ok to me but please remove the commit that adds all these _ before variables. Also don't remove SDL_GetRevisionNumber if the function still exists in SDL. It has been bound, people may be using it, there's no need to break them.

[pirbo]

Done both

• the _ thing was to please ocamlopt "unused variable" warning (which dune activates and even turns into an error but right completely unrelated)
• yes SDL_GetRevisionNumber BUT if you try to use it statically (which we "do" once we generate the binding using stubs), your C compiler does emit a big warning that the function is deprecated and SDL devs want you to not use it anymore :)

[dbuenzli]

Why are you removing these constants ?

[pirbo]

I'm not. These are duplicates (look 5 lines above in this example)

[dbuenzli]

Ah yes thanks!

[dbuenzli]

Thanks they have been merged, could you please rebase your other PRs so that they are simpler to inspect.