With the switch to the hermetic toolchain, the clang-tidy invoked by the xls/dev_tools/run-clang-tidy-cached.sh script does not find the system headers anymore, making the report useless as it is mostly clang-diagnostic-error now (and once there is a diagnostic error in a file, the whole report for that file is typically bogus).
So: find a way to properly configure clang-tidy to find the system headers that came packaged with that toolchain.