Replace sprintf with snprintf (to address g++ warnings).

SNFMulti.cpp

@@ -298,7 +298,9 @@ string FileUTC(string FileName) {
 
     char TimestampBfr[20];                                                      // Timestamp buffer.
 
-    sprintf(TimestampBfr,"%04d%02d%02d%02d%02d%02d",                            // Format yyyymmddhhmmss
+    size_t l = snprintf(                                                        // Format yyyymmddhhmmss
+      TimestampBfr, sizeof(TimestampBfr),
+      "%04d%02d%02d%02d%02d%02d",
       FileNameTime.tm_year+1900,
       FileNameTime.tm_mon+1,
       FileNameTime.tm_mday,