Fixed leaking consts from tinyxml2

Author: qjgn

External/tinyxml2.README.md

@@ -14,6 +14,31 @@ The following files have been copied to `External/tinyxml2`:
 - `LICENSE.txt`  
 - `readme.txt`  
 
+### Applied the following patch to hide leaking consts
+
+```
+diff --git a/External/tinyxml2/tinyxml2.cpp b/External/tinyxml2/tinyxml2.cpp
+index 083f54b..db7b53b 100644
+--- a/External/tinyxml2/tinyxml2.cpp
++++ b/External/tinyxml2/tinyxml2.cpp
+@@ -119,6 +119,8 @@ distribution.
+        #define TIXML_FTELL ftell
+ #endif
+
++namespace
++{
+
+ static const char LINE_FEED                            = static_cast<char>(0x0a);                      // all line endings are normalized to LF
+ static const char LF = LINE_FEED;
+@@ -135,6 +137,8 @@ static const unsigned char TIXML_UTF_LEAD_0 = 0xefU;
+ static const unsigned char TIXML_UTF_LEAD_1 = 0xbbU;
+ static const unsigned char TIXML_UTF_LEAD_2 = 0xbfU;
+
++}
++
+ namespace tinyxml2
+ {
+```
 ## Usage
 `tinyxml2` is referenced by source and built together with the target.