When i gave the command in zebra after ./configure make it shows the errors I. -I. -I.. -I.. -I.. -I../lib -g -O2 -Wall -c `test -f 'rtadv.c' || echo './'`rtadv.c rtadv.c: In function ?rtadv_recv_packet?: rtadv.c:123: error: dereferencing pointer to incomplete type rtadv.c:124: error: dereferencing pointer to incomplete type rtadv.c:124: error: dereferencing pointer to incomplete type rtadv.c: In function ?rtadv_send_packet?: rtadv.c:149: error: invalid application of ?sizeof? to incomplete type ?struct in6_pktinfo? rtadv.c:194: warning: operation on ?node? may be undefined rtadv.c:268: error: dereferencing pointer to incomplete type rtadv.c:269: error: dereferencing pointer to incomplete type rtadv.c: In function ?rtadv_prefix_lookup?: rtadv.c:476: warning: operation on ?node? may be undefined rtadv.c: In function ?rtadv_config_write?: rtadv.c:977: warning: operation on ?node? may be undefined rtadv.c:982: warning: pointer targets in passing argument 3 of ?inet_ntop? differ in signedness make[2]: *** [rtadv.o] Error 1 make[2]: Leaving directory `/home/valli/Desktop/zebra-0.95a/zebra' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/home/valli/Desktop/zebra-0.95a' make: *** [all] Error 2