Fix API tests for object

Because of a typo in test/testprogs/Makefile.am, the tests for object
were never compiled or run.

test/testprogs/Makefile.am

@@ -3,7 +3,7 @@ check_PROGRAMS = test_array test_simple test_number test_object
 test_array_SOURCES = test_array.c util.h
 test_simple_SOURCES = test_simple.c util.h
 test_number_SOURCES = test_number.c util.h
-test_object_SOURCES = test_number.c util.h
+test_object_SOURCES = test_object.c util.h
 
 AM_CPPFLAGS = -I$(top_srcdir)/src
 AM_CFLAGS = -Wall -Werror

test/testprogs/test_object.c

@@ -6,11 +6,13 @@
  */
 
 #include <jansson.h>
+#include <string.h>
 #include "util.h"
 
 int main()
 {
     json_t *object, *string, *other_string, *value;
+    void *iter;
 
     object = json_object();
     string = json_string("test");