Collecting the following updates: - Updated the "standalone externals" to be in sync with LCG_93, and updated AthAnalysisExternals to build against LCG_93; - Updated the CPack configuration to only build TGZ files on macOS; - Some small tweaks to how the python byte-code building targets would show up in IDEs like Xcode; - Update to atlas_add_test(...) to allow using any directory as the run directory for a given test; - Taught the code not to pick up .git/ directories while installing a release (relevant only for analysis repositories); - Added an optional NOEXEC argument to atlas_add_test(...) to allow for tests where the success of the build is the test itself; - Added Findlibffi.cmake to be able to set up this library for the runtime environment, which LCG_91's glib installation depends on.