reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/djiang/linux.git/commit/?id=50bb7ff9edf14d384d8cd902ac40e41abee77651
        git remote add djiang https://git.kernel.org/pub/scm/linux/kernel/git/djiang/linux.git
        git fetch --no-tags djiang cxl/fwctl
        git checkout 50bb7ff9edf14d384d8cd902ac40e41abee77651
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash