kernel_netlink.c: don't include <linux/if_bridge.h>

In order to address this, this patch removes the <linux/if_bridge.h>
inclusion, and instead defines BRCTL_GET_BRIDGES to the appropriate
value if it's not provided by the C library.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

kernel_netlink.c

@@ -39,10 +39,14 @@ THE SOFTWARE.
 #include <sys/socket.h>
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
-#include <linux/if_bridge.h>
 #include <linux/fib_rules.h>
 #include <net/if_arp.h>
 
+/* From <linux/if_bridge.h> */
+#ifndef BRCTL_GET_BRIDGES
+#define BRCTL_GET_BRIDGES 1
+#endif
+
 #if(__GLIBC__ < 2) || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 5)
 #define RTA_TABLE 15
 #endif