reproduce (this is a W=1 build):
        git remote add uml https://git.kernel.org/pub/scm/linux/kernel/git/uml/linux
        git fetch uml next
        git checkout uml/next
        b4 shazam https://lore.kernel.org/r/5a769da2dcc8e7f9b89fbdbc4bccd0b8a1660309.1731290567.git.thehajime@gmail.com
        # 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 arch/um/os-Linux/