reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc.git/commit/?id=74a3fe7c3784c8cae2e3e14c0078f33c1468fefc
        git remote add ulfh-mmc git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc.git
        git fetch --no-tags ulfh-mmc next
        git checkout 74a3fe7c3784c8cae2e3e14c0078f33c1468fefc
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/mmc/host/