#include <pcap-types.h>
#ifdef _WIN32
+/*
+ * Make sure Packet32.h doesn't define BPF structures that we've
+ * probably already defined as a result of including <pcap/pcap.h>.
+ */
+#define BPF_MAJOR_VERSION
#include <Packet32.h> /* for PacketGetVersion() */
#else
#include <sys/param.h>