reproduce (this is a W=1 build):
        # https://github.com/isilence/linux/commit/7d14efdc8782b0359d840b3434d06415162da138
        git remote add isilence https://github.com/isilence/linux
        git fetch --no-tags isilence zcrx/v5
        git checkout 7d14efdc8782b0359d840b3434d06415162da138
        # 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 net/ipv4/