reproduce (this is a W=1 build):
        git checkout next-20260121
        b4 shazam https://lore.kernel.org/r/20260121225438.3908422-7-jmattson@google.com
        # apt-get install llvm-dev

        # save the config file
        make W=1 ARCH=x86_64 olddefconfig
        make W=1 ARCH=x86_64 
        make W=1 headers
        make W=1 -C tools/testing/selftests