Porting to zig 0.9.0

[realgdman]

Hello, I'm new to zig and don't have a PR, but here's my findings on what need to be changed

1. Allocator now is object itself, not pointer
   1.1. Replace declarations allocator: *Allocator with allocator: Allocator
   1.2. Replace usage &allocator.allocator with allocator.allocator()
   There are cases with ?Allocator, I'm not sure if that's valid.
2. Mutex is now locking itself, doesn't return held object
   2.1. Replace declarations: held: blabla @TypeOf(std.Thread.Mutex.acquire)... to mutex: std.Thread.Mutex
   2.2. Replace lock held = lock.acquire() to mutex.lock()
   2.3. Replace defer held.release() to defer mutex.unlock() and held.release() to mutex.unlock()
3. c_void changed to anyopaque. Not sure, may be it need to be *allowzero anyopaque.
4. There is package in buld.zig that named zlm but refers to zalgebra, not sure if they're interchangable
5. Example in README.md somewhat outdated, I have changed some parts according to karts example
   5.1. Changed .rotation = Vec3.new(-120.0, -15.0, 0).toRadians() to .rotation = Quat.fromEulerAngle(Vec3.new(-120, -15, 0))
   5.2. primitive name need to be asset var cube = try didot_obj.GameObject.createObject(allocator, asset.get("Mesh/Cube"));
   asset is referenced as const asset = &app.scene.assetManager;
   5.3. usingnamespace @import(...) not working anymore, I ended up with const didot_gfx = @import("didot-graphics"); etc.
6. Some deprecated std.debug.warn changed to std.debug.print

This is where I ended up now. I have trouble building glfw on windows, so I replaced all cImports with https://github.com/JonSnowbd/ZT/ but that's another story.

[zenith391]

Thanks!
It's been long since I have touched Didot's code (last commit was October last year!) but I'll try to address those issues in the current week and maybe work a bit on adding a few new features to Didot. I'll close this issue once it compiles on Zig 0.9.0

[realgdman]

Hello, I have made some progress (basic rendering on windows- im using ZT for GL, mouselook - disabled physics for now).
I'll post link here, it's pretty messed up, but probably have some use for reference. https://github.com/realgdman/didot

Have no idea why karts going purple.