macOS: Add build configuration

[tuxuser]

This commit adds support for building on macOS (tested via Github CI workflow).

• Add macOS premake5 binary
• Add linkoptions for macOS
• Extend GLFW premake file with macOS filter
• Extend platform detection

The GLFW addition is also sent upstream (https://github.com/simonri/glfw-premake/pull/1)