Update bindings to raylib 3.8.1 (master)

[Willenbrink]

This PR updates the raylib bindings to the current repository version (3.8.1 or 4.0, the repo is not consistent on this). I assume that you want to stick to official releases. Apparently 4.0 will release sometime in November but I might be busy by then so here is my current version in case you want to use this for porting to 4.0 or anyone wants to use a more recent version before then.

Summary of the changes:

• [x] Include config.h in raylib_constants because MAX_MATERIAL_MAPS is defined there
• [x] Rename structs
• [x] Update function names and arguments
• [x] Update version to 3.8.1
• [x] Update diff patch for linux
• [x] Update examples/core/core_3d_picking.ml
• [x] Update the diffs for other platforms
• [x] Update raygui bindings

[tjammer]

Nice, thanks for the effort! I have nothing against staying closer to the raylib HEAD! So far I didn't do it because the official releases worked for me and I hoped that there might be less bugs than at HEAD (not that I ever had problems with bugs in raylib). And when we're at 3.8 the eventual bump to 4.0 will be easier in the future.

[Willenbrink]

Good to hear! I've just updated the raygui bindings as it was quite easy. In general, I've not checked for functions present in raylib/raygui that are missing from the bindings because I have no idea how to do that automatically. I guess that's not too much of a problem. It would be nice if you could take a look at the diffs for BSD and Windows as I develop on neither though I believe that nothing has to be changed. Besides that, the PR should be ready to be merged.

[tjammer]

The CI windows build is successful and I just built the branch on FreeBSD successfully, so it seems everything works. Again, many thanks for this!