Adding missing headers

Author: srdja

test/array_test.c

@@ -1,3 +1,5 @@
+#include <time.h>
+
 #include "../src/array.h"
 #include "test.h"
 

test/list_test.c

@@ -8,6 +8,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include "../src/list.h"
 #include "test.h"
 

test/slist_test.c

@@ -1,6 +1,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include "../src/slist.h"
 #include "test.h"