ANDROID: fix build for missing ETH_ALEN definition am: 7608e136bd am: 3799b1e13f am: f751c1415e

Original change: https://android-review.googlesource.com/c/platform/external/iptables/+/1650937

Change-Id: I2d1d6c9df66bb0908ecd75f3ddba7712819ff6a8
diff --git a/libxtables/xtables.c b/libxtables/xtables.c
index 9d309e3..35fa625 100644
--- a/libxtables/xtables.c
+++ b/libxtables/xtables.c
@@ -45,6 +45,9 @@
 
 #include <xtables.h>
 #include <limits.h> /* INT_MAX in ip_tables.h/ip6_tables.h */
+#ifdef __BIONIC__
+#include <linux/if_ether.h> /* ETH_ALEN */
+#endif
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <linux/netfilter_ipv6/ip6_tables.h>
 #include <libiptc/libxtc.h>