Which system，This code can build.

[lokenetwork]

[chenshuo]

Linux

[ohmyadd]

ubuntu 16.04 server i386

[songsmith]

Linux Centos7 core 3.10.0-229.20.1.el7.x86_64 ，build faild.

`+ ar rcs objs/libnetinet.a objs/handshake.o objs/if_ether.o objs/if_ethersubr.o objs/if_loop.o objs/if.o objs/if_pigeon.o objs/if_tun.o objs/igmp.o objs/in_cksum.o objs/init.o objs/in.o objs/in_pcb.o objs/in_proto.o objs/ip_icmp.o objs/ip_input.o objs/ip_intercept.o objs/ip_output.o objs/kern_subr.o objs/pcap.o objs/ping.o objs/radix.o objs/raw_ip.o objs/route.o objs/stub.o objs/sys_socket.o objs/tcp_debug.o objs/tcp_input.o objs/tcp_output.o objs/tcp_subr.o objs/tcp_timer.o objs/tcp_usrreq.o objs/trace.o objs/udp_usrreq.o objs/uipc_domain.o objs/uipc_mbuf.o objs/uipc_socket2.o objs/uipc_socket.o

• gcc -m64 -g -Wall tests/init.c -o objs/test_init objs/libnetinet.a objs/libnetinet.a(if_loop.o): In function looutput': /home/project/4.4BSD-Lite2/sys/net/if_loop.c:178: undefined reference to setsoftnet' objs/libnetinet.a(if_ethersubr.o): In function ether_input': /home/project/4.4BSD-Lite2/sys/net/if_ethersubr.c:334: undefined reference to setsoftnet' /home/project/4.4BSD-Lite2/sys/net/if_ethersubr.c:339: undefined reference to `setsoftnet' collect2: error: ld returned 1 exit status
• gcc -m64 -g -Wall tests/pigeon.c -o objs/test_pigeon objs/libnetinet.a tests/pigeon.c: In function 'main': tests/pigeon.c:51:18: warning: unused variable 'clientso' [-Wunused-variable] struct socket* clientso = connectto(0xc0a80001, 1234); ^ objs/libnetinet.a(if_loop.o): In function looutput': /home/project/4.4BSD-Lite2/sys/net/if_loop.c:178: undefined reference to setsoftnet' objs/libnetinet.a(if_ethersubr.o): In function ether_input': /home/project/4.4BSD-Lite2/sys/net/if_ethersubr.c:334: undefined reference to setsoftnet' /home/project/4.4BSD-Lite2/sys/net/if_ethersubr.c:339: undefined reference to `setsoftnet' collect2: error: ld returned 1 exit status
• gcc -m64 -g -Wall tests/tun.c -o objs/test_tun objs/libnetinet.a objs/libnetinet.a(if_loop.o): In function looutput': /home/project/4.4BSD-Lite2/sys/net/if_loop.c:178: undefined reference to setsoftnet' objs/libnetinet.a(if_ethersubr.o): In function ether_input': /home/project/4.4BSD-Lite2/sys/net/if_ethersubr.c:334: undefined reference to setsoftnet' /home/project/4.4BSD-Lite2/sys/net/if_ethersubr.c:339: undefined reference to setsoftnet'