BUILD: udp: include tools.h from proto_udp.c
A few functions are used from there for address conversion but the
file wasn't included.
diff --git a/src/proto_udp.c b/src/proto_udp.c
index 56d3518..f07170f 100644
--- a/src/proto_udp.c
+++ b/src/proto_udp.c
@@ -39,6 +39,7 @@
#include <haproxy/sock.h>
#include <haproxy/sock_inet.h>
#include <haproxy/task.h>
+#include <haproxy/tools.h>
static int udp_bind_listener(struct listener *listener, char *errmsg, int errlen);
static void udp_enable_listener(struct listener *listener);