reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1
        git remote add android-common https://android.googlesource.com/kernel/common
        git fetch --no-tags android-common android15-6.6
        git checkout 458cdb59f7719f81504d392daa95a8c99c30c276
        # 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=i386 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=i386 SHELL=/bin/bash drivers/android/