reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor.git/commit/?id=102ada7ca37ed8358bd70c6f8e6475ebacf6f76d
        git remote add jj-apparmor https://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor.git
        git fetch --no-tags jj-apparmor apparmor-next
        git checkout 102ada7ca37ed8358bd70c6f8e6475ebacf6f76d

        # install sparc64 cross compiling tool for clang build
        # apt-get install binutils-sparc64-linux-gnu
        # clang-22 might not be officially released. Try a lower version if installation fails.
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=sparc64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=sparc64 SHELL=/bin/bash security/apparmor/