Sebastian Meyer enhanced the build-time reliability of the EmilHvitfeldt/xgboost R package by focusing on cross-platform compatibility and robust error handling. He implemented targeted C++ and shell-based build system configuration changes, introducing checks for backtrace and fopen64 to prevent install-time failures across Windows, macOS, and Linux. By conditionally defining DMLC-related macros and refining endianness detection logic, Sebastian ensured consistent runtime behavior and smoother installation experiences. His updates to Makevars.in propagated these improvements throughout the build process. The work demonstrated a deep understanding of cross-platform development and build system intricacies, resulting in a more stable and portable R package.