Alex Christensen focused on stabilizing the build system for the achristensen07/WebKit repository, targeting improved cross-platform support and 32-bit compatibility. He addressed a 32-bit compilation issue by updating GResources.cpp to include the necessary mutex header, ensuring successful builds on legacy architectures. Additionally, Alex modified CMakeLists.txt to make bmalloc support optional, allowing system malloc to be used when appropriate and reducing dependency-related build failures. Working primarily with C++ and CMake, he enhanced the reliability and portability of the build process. His contributions reflect a targeted, in-depth approach to build system configuration and cross-platform C++ development within WebKit.