reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/commit/?id=be8468b5e108830e2057b00a3ac27e882fd499d1
        git remote add rt-devel https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
        git fetch --no-tags rt-devel linux-6.10.y-rt-rebase
        git checkout be8468b5e108830e2057b00a3ac27e882fd499d1
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash