Set preprocessor conformance in vc++.

Author: evoskuil

builds/msvc/properties/Common.props

@@ -27,7 +27,7 @@
 
       <!-- Language -->
       <!-- /Zc is conformance mode. -->
-      <AdditionalOptions>/Zc:__cplusplus %(AdditionalOptions)</AdditionalOptions>
+      <AdditionalOptions>/Zc:__cplusplus /Zc:preprocessor %(AdditionalOptions)</AdditionalOptions>
       <EnforceTypeConversionRules>true</EnforceTypeConversionRules>
       <RuntimeTypeInfo>true</RuntimeTypeInfo>
       <OpenMPSupport>false</OpenMPSupport>