*: 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/tests/test-cli.c b/tests/test-cli.c
index 3db44ee..6fab6d5 100644
--- a/tests/test-cli.c
+++ b/tests/test-cli.c
@@ -20,6 +20,8 @@
  * 02111-1307, USA.
  */
 
+#include <zebra.h>
+
 #include "common-cli.h"
 
 DUMMY_DEFUN(cmd0,  "arg ipv4 A.B.C.D");