reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git/commit/?id=d45011bbc88d112e7eea4dbb9a1b3b0081d0b30a
        git remote add zohar-integrity https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git
        git fetch --no-tags zohar-integrity next-integrity.ima-sigv3-support-1
        git checkout d45011bbc88d112e7eea4dbb9a1b3b0081d0b30a

        # 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