Matt worked on improving the Ghostunnel package in the hmemcpy/nixpkgs repository by addressing a critical build compatibility issue for macOS. He resolved persistent build failures by adding missing build inputs and adjusting test flags, ensuring the package now compiles and tests correctly on Darwin systems. Leveraging his expertise in Nix and build system configuration, Matt enhanced the reliability of cross-platform continuous integration for Ghostunnel. This work reduced macOS-specific build failures and accelerated release cycles, resulting in more stable deployments for dependent services. His focused approach demonstrated a strong understanding of cross-platform development and the intricacies of the Nix build ecosystem.