reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git/commit/?id=3e5ba97c181e32ca9b810414272b57bb7600998e
        git remote add efi https://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git
        git fetch --no-tags efi next
        git checkout 3e5ba97c181e32ca9b810414272b57bb7600998e

        # 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