ENH: Remove more warnings

Source/CTest/Curl/Testing/curltest.c

@@ -1,6 +1,9 @@
+// Prevent warnings on Visual Studio
 struct _RPC_ASYNC_STATE;
+
 #include "curl/curl.h"
 #include <stdlib.h>
+#include <string.h>
 
 int GetFtpFile(void)
 {