Make test_checkdir.c dirent include consistent with other files

src/test/test_checkdir.c

@@ -4,7 +4,9 @@
 #include "orconfig.h"
 #include "or.h"
 
-#ifndef _WIN32
+#ifdef _WIN32
+#include <direct.h>
+#else
 #include <dirent.h>
 #endif