reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?id=4974c93ce402d69988eb7b2e9e490c22cc22bb7b
        git remote add peterz-queue https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git
        git fetch --no-tags peterz-queue sched/flat
        git checkout 4974c93ce402d69988eb7b2e9e490c22cc22bb7b

        # 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 kernel/sched/