C++: Use correct features for document parsing

Task-number: QTCREATORBUG-8007
Change-Id: Ic96aaa433442812a99bac9d16bb9124d66762e8c
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/plugins/qmakeprojectmanager/qmakeproject.cpp

@@ -538,6 +538,8 @@ void QmakeProject::updateCppCodeModel()
         // part->precompiledHeaders
         templatePart->precompiledHeaders.append(pro->variableValue(PrecompiledHeaderVar));
 
+        templatePart->updateLanguageFeatures();
+
         ProjectPart::Ptr cppPart = templatePart->copy();
         { // C++ files:
             // part->files