Zig 0.15

[aveyrenc]

I'm new to Zig and am welcome to suggestions on how to improve this PR.

With zig build run -Doptimize=ReleaseFast I get similar performance than on 0.14, but with the default (Debug) optimize I get less than half of the FPS. That's why I updated the README to use ReleaseFast.

Fixes #30

[ashugg]

Works for me on macOS 14.7.8 with zig 0.15.1

gh repo clone gh repo clone const-void/DOOM-fire-zig

cd DOOM-fire-zig

git checkout zig-0.15

gh pr checkout 31

zig build run

Code built and ran successfully

I assume the checkout to the zig-0.15 branch is necessary, as we don't want PR 31 to affect users with Zip 0.14