rule: Fix build failure in rule.c

Commit c8a0e8c90 added #include <linux/netfilter_bridge.h> but that header needs
the definition of IFNAMSIZ from <net/if.h>
Sample build failure:

  CC       evaluate.lo
In file included from ../include/linux/netfilter_bridge.h:10:0,
                 from rule.c:32:
/usr/include/linux/if_pppox.h:42:20: error: 'IFNAMSIZ' undeclared here (not in a function)
  char          dev[IFNAMSIZ];          /* Local device to use */
                    ^
Makefile:687: recipe for target 'rule.lo' failed

Signed-off-by: Duncan Roe <duncan_roe@optusnet.com.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/rule.c b/src/rule.c
index d11b1d29..570d6671 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -29,6 +29,7 @@
 #include <linux/netfilter.h>
 #include <linux/netfilter_arp.h>
 #include <linux/netfilter_ipv4.h>
+#include <net/if.h>
 #include <linux/netfilter_bridge.h>
 
 void handle_free(struct handle *h)