Worked on the macports/macports-ports repository to enhance compatibility and stability for legacy macOS environments. Focused on build engineering and MacPorts, the developer addressed a bug in the libheif Portfile by updating its fallback logic to support macOS 10.12 and earlier when using libc++. This adjustment ensures that users on older systems can continue building packages with pre-C++20 toolchains, reducing the risk of build failures and maintaining package availability. The work required a detailed understanding of macOS system constraints and Portfile scripting, demonstrating careful attention to backward compatibility and the nuances of supporting diverse macOS versions in open source projects.