Worked on enhancing the build-time reliability of the EmilHvitfeldt/xgboost R package, focusing on cross-platform compatibility and error handling. Developed a targeted patch in C++ and Shell that introduced build-time checks for backtrace and fopen64, ensuring smoother installation across Windows, macOS, and Linux. The approach involved conditionally defining DMLC-related macros based on detected system functions and refining endianness detection logic to maintain runtime consistency. Updates to Makevars.in propagated these new definitions, further stabilizing the build process. This work improved the robustness of the package’s build system configuration, reducing install-time failures and supporting a more reliable developer experience.