diff --git a/src/sniffer.c b/src/sniffer.c
index 68ece0d1b6..e055a8a127 100644
--- a/src/sniffer.c
+++ b/src/sniffer.c
@@ -19,6 +19,10 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  */
 
+#ifdef HAVE_IO_POOL
+    #include <stdlib.h>
+#endif
+
 #ifdef HAVE_CONFIG_H
     #include <config.h>
 #endif