win: _set_ouput_format is no longer available or required on VS2015

Source/core/css/CSSPrimitiveValue.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 808 matching lines @@
         return propertyName(m_value.propertyID);
     default:
         break;
     }
 
     return String();
 }
 
 static String formatNumber(double number, const char* suffix, unsigned suffixLength)
 {
-#if OS(WIN)
+#if OS(WIN) && _MSC_VER < 1900
     unsigned oldFormat = _set_output_format(_TWO_DIGIT_EXPONENT);
 #endif
     String result = String::format("%.6g", number);
-#if OS(WIN)
+#if OS(WIN) && _MSC_VER < 1900
     _set_output_format(oldFormat);
 #endif
     result.append(suffix, suffixLength);
     return result;
 }
 
 template <unsigned characterCount>
 ALWAYS_INLINE static String formatNumber(double number, const char (&characters)[characterCount])
 {
     return formatNumber(number, characters, characterCount - 1);
@@ skipping 291 matching lines @@
         visitor->trace(m_value.shape);
         break;
     default:
         break;
     }
 #endif
     CSSValue::traceAfterDispatch(visitor);
 }
 
 } // namespace blink