Fix failing build on macOS

[ohrite]

Description

Include OpenGL/gl3.h on macOS in c_src/defvice/gl_helpers.c

Motivation and Context

I'm building the latest head of main on macOS Ventura, and ran into a classic macOS OpenGL header issue: fatal error: 'GLES3/gl3.h' file not found.

It appears this issue was introduced in https://github.com/ScenicFramework/scenic_driver_local/commit/51f91bf17d0ccec250508b6558efb909e96d1c87

The codebase is already using the __APPLE__ cpp directive for conditional includes in c_src/nanovg/nanovg_gl_utils.h for similar reasons.

Types of changes

• [ ] Bug fix (a non-breaking change which fixes an issue)
• [ ] New feature (a non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] Improvement/refactoring (non-breaking change that doesn't add any feature but make things better)

Checklist

• [x] Check other PRs and make sure that the changes are not done yet.

[crertel]

Thanks for this!

[axelson]

I'm not sure how to trigger the build on this. I'm going to go ahead and merge.

[axelson]

And the build succeeded on main: https://github.com/ScenicFramework/scenic_driver_local/actions/runs/5845487259/job/15849656829