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/hyperv/linux.git/commit/?id=1b201a9393f76966b25219b0ecc25c1697fc780a
        git remote add hyperv https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git
        git fetch --no-tags hyperv hyperv-next-staging
        git checkout 1b201a9393f76966b25219b0ecc25c1697fc780a
        # 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 drivers/hv/