--- ./src/wifipcap/wifipcap.cpp.orig	2013-12-27 17:57:48.000000000 +0000
+++ ./src/wifipcap/wifipcap.cpp	2013-12-28 16:20:01.000000000 +0000
@@ -1735,6 +1735,13 @@
 const char *Wifipcap::SetFilter(const char *filter)
 {
     struct bpf_program fp;
+/*
+ * libpcap from FreeBSD 8 does not have PCAP_NETMASK_UNKNOWN
+ * According to pcap_compile(3) a value of 0 can be supplied
+ */
+#ifndef PCAP_NETMASK_UNKNOWN
+#define PCAP_NETMASK_UNKNOWN 0
+#endif
     bpf_u_int32 netp=PCAP_NETMASK_UNKNOWN;
 
     if(pcap_compile(descr,&fp,(char *)filter,0,netp) == -1) {