diff --git a/src/core.c b/src/core.c
index 97b01a9..b0e3f21 100644
--- a/src/core.c
+++ b/src/core.c
@@ -15,7 +15,7 @@
  *                                                                         *
  ***************************************************************************/
 #include <sys/types.h>
-//#include <sys/cdefs.h>
+#include <sys/cdefs.h>
 
 #include <stdio.h>
 #include <unistd.h>