reproduce (this is a W=1 build):
        # https://github.com/jcmvbkbc/linux-xtensa/commit/dcd699a99ce2f40e50263e0ec438e3b57b133598
        git remote add jcmvbkbc-xtensa https://github.com/jcmvbkbc/linux-xtensa
        git fetch --no-tags jcmvbkbc-xtensa pr/24
        git checkout dcd699a99ce2f40e50263e0ec438e3b57b133598

        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=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/