Fix redefined(_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES) warning

Author: terrycz126

src/lib_json/json_reader.cpp

@@ -27,11 +27,16 @@
 #endif
 #else
 #include <cstdio>
+#endif //__cplusplus
 
 #if defined(_MSC_VER)
+#if !defined(_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES)
 #define _CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES 1
-#endif
-#endif
+#endif  //_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES
+#if !defined(snprintf)
+#define snprintf _snprintf
+#endif  //snprintf
+#endif  //_MSC_VER
 
 #if defined(_MSC_VER) && _MSC_VER >= 1400 // VC++ 8.0
 // Disable warning about strdup being deprecated.