*: make sure zebra.h is always included first

zebra.h pulls in config.h, which results in fiddling with things like
__FILE_OFFSET_BITS. It must always be included first, in order to set
flags that influence the compiler via <features.h>.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/lib/stream.c b/lib/stream.c
index 9c26fea..ca1a40f 100644
--- a/lib/stream.c
+++ b/lib/stream.c
@@ -20,8 +20,8 @@
  * 02111-1307, USA.  
  */
 
-#include <stddef.h>
 #include <zebra.h>
+#include <stddef.h>
 
 #include "stream.h"
 #include "memory.h"