reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git/commit/?id=5b80f3b3cea35ea00ce9d14357e3ec65416bdcb0
        git remote add tglx-devel https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git
        git fetch --no-tags tglx-devel locking/futex
        git checkout 5b80f3b3cea35ea00ce9d14357e3ec65416bdcb0

        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 kernel/futex/