reproduce (this is a W=1 build):
        # https://github.com/sean-jc/linux/commit/9796c520977c647c82515987b362119c7c4593ed
        git remote add sean-jc https://github.com/sean-jc/linux
        git fetch --no-tags sean-jc rev/get_set_guest_clock
        git checkout 9796c520977c647c82515987b362119c7c4593ed

        # 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