inet_diag: Older kernels don't include linux/types.h in netlink.h

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/python-inet_diag/inet_diag.c b/python-inet_diag/inet_diag.c
index 63c7a23..7cfc7f5 100644
--- a/python-inet_diag/inet_diag.c
+++ b/python-inet_diag/inet_diag.c
@@ -20,6 +20,7 @@
 
 #include <errno.h>
 #include <sys/socket.h>
+#include <linux/types.h>
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
 #include <arpa/inet.h>