diff --git a/src/backend/evhttp.c b/src/backend/evhttp.c
index a6028ad..ca43bc0 100644
--- a/src/backend/evhttp.c
+++ b/src/backend/evhttp.c
@@ -33,6 +33,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <evhttp.h>
diff --git a/src/backend/zmq.c b/src/backend/zmq.c
index d48a8ba..b414ea2 100644
--- a/src/backend/zmq.c
+++ b/src/backend/zmq.c
@@ -36,6 +36,7 @@
 #include <math.h>
 
 #include <zmq.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <jansson.h>