--- D:/Toolkits/Qt/qt-everywhere-enterprise-src-5.9.0-beta/qtwebengine/src/3rdparty/ninja/src/includes_normalize-win32.cc.bkp	Tue Mar 28 14:41:54 2017
+++ D:/Toolkits/Qt/qt-everywhere-enterprise-src-5.9.0-beta/qtwebengine/src/3rdparty/ninja/src/includes_normalize-win32.cc	Wed Apr 12 23:01:52 2017
@@ -61,7 +61,7 @@
 
 string IncludesNormalize::ToLower(const string& s) {
   string ret;
-  transform(s.begin(), s.end(), back_inserter(ret), ::tolower);
+  transform(s.begin(), s.end(), back_inserter(ret), [](const char c) { return static_cast<char>(::tolower(c)); });
   return ret;
 }