The nwfilter code uses ETH_ALEN, which isn't defined on MacOS X.
This is a simple workaround, to add it when missing.
---
src/nwfilter/nwfilter_learnipaddr.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/src/nwfilter/nwfilter_learnipaddr.c b/src/nwfilter/nwfilter_learnipaddr.c
index 7c94fc2..554422b 100644
--- a/src/nwfilter/nwfilter_learnipaddr.c
+++ b/src/nwfilter/nwfilter_learnipaddr.c
@@ -38,6 +38,11 @@
#include <net/if_arp.h>
#include <intprops.h>
+// Add Linux define missing from OSX
+#ifndef ETH_ALEN
+#define ETH_ALEN 6 /* Octets in one ethernet addr */
+#endif
+
#include "internal.h"
#include "buf.h"
--
1.7.2.3