Update tinyxml2.h

*end != 0 => *_end != 0
diff --git a/tinyxml2.h b/tinyxml2.h
index b75471f..b0636a4 100755
--- a/tinyxml2.h
+++ b/tinyxml2.h
@@ -172,7 +172,7 @@
         NEEDS_DELETE = 0x200

     };

 

-    // After parsing, if *end != 0, it can be set to zero.

+    // After parsing, if *_end != 0, it can be set to zero.

     int     _flags;

     char*   _start;

     char*   _end;