reproduce (this is a W=1 build):
        # https://github.com/zen-kernel/zen-kernel/commit/6e3d1052d6a5a242fc1769fa2fcec7707c38ba98
        git remote add zen https://github.com/zen-kernel/zen-kernel
        git fetch --no-tags zen pr/339
        git checkout 6e3d1052d6a5a242fc1769fa2fcec7707c38ba98
        # 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 drivers/video/fbdev/core/