time support: For portability, also include <time.h>
diff --git a/ndn-cpp/c/util/time.c b/ndn-cpp/c/util/time.c
index b7de490..5a74466 100644
--- a/ndn-cpp/c/util/time.c
+++ b/ndn-cpp/c/util/time.c
@@ -4,6 +4,7 @@
  * See COPYING for copyright and distribution information.
  */
 
+#include <time.h>
 #include <sys/time.h>
 #include <math.h>
 #include <string.h>