build.zig: Re-add OpenGL to Linux deps

[sagehane]

Of course, being dumb, I forgot to test the damn thing with an actual binary and got hit by missing OpenGL issues at runtime. Sigh

[raysan5]

@sagehane Thanks for the update... please, note that I'm not testing all those changes and a new raylib release is around the corner, build.zig should be as much stable as possible...

[sagehane]

I'm very sorry about all the sloppiness on my part. AFAIK, there is one more bug with the build system at #4407 (review) and that should be everything. I'll extract that to a separate PR and focus on reviewing the PRs more carefully and understanding this repo until the next release. Everything else would classify as enhancements over the existing setup and wouldn't be required. Aside from that, the fact that I haven't been able to check how Raygui works with the current build system is slightly concerning, but I don't think I would have introduced breaking errors.