reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/melver/linux.git/commit/?id=984de4f8d618b9302bf2f459e217768752f39a69
        git remote add melver https://git.kernel.org/pub/scm/linux/kernel/git/melver/linux.git
        git fetch --no-tags melver ctx-analysis/dev
        git checkout 984de4f8d618b9302bf2f459e217768752f39a69

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um olddefconfig
        make W=1 O=build_dir ARCH=um SHELL=/bin/bash lib/