reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1
        # https://github.com/l1k/linux/commit/2fb114bf74eff73c83383cbd1d481584053cb8cd
        git remote add l1k https://github.com/l1k/linux
        git fetch --no-tags l1k mariusz-npem
        git checkout 2fb114bf74eff73c83383cbd1d481584053cb8cd
        # 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=x86_64 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/pci/