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/20250924142059.527768-10-benjamin@sipsolutions.net
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=um olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=um SHELL=/bin/bash