reproduce (this is a W=1 build):
        # https://github.com/isilence/linux/commit/e1154ae207d2ef9599be621dbec9a702e73e7db8
        git remote add isilence https://github.com/isilence/linux
        git fetch --no-tags isilence zcrx/next
        git checkout e1154ae207d2ef9599be621dbec9a702e73e7db8
        # 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/