Add experimental clang code-model plug-in.

Previously known as the wip/clang branch.

Contributors (in alphabetical order):
- Christian Kamm <christian.d.kamm@nokia.com>
- Erik Verbruggen <erik.verbruggen@digia.com>
- Leandro Melo <leandro.melo@nokia.com>
- Peter Kuemmel <syntheticpp@gmx.net>
- Sergey Shambir <sergey.shambir.auto@gmail.com>

Change-Id: I4c3ff600a19b6732641c1d5ef28236bf2cc17737
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/cpptools/cppchecksymbols.h

@@ -42,6 +42,17 @@
 
 namespace CppTools {
 
+#ifdef _MSC_VER
+// Short explanation: QFutureInterface is currently used as a base for an exported class
+// (see CreateMarkers). Even though it's not explicitly marked to be exported VC++ will
+// implicitly export it (more details on the General Rules and Limitations of dllexport/
+// dllimport MSDN page). When seen here as a base of CheckSymbols the compiler tries to
+// instantiate this template (since the declaration of template doesn't have any explicit
+// export/import attribute) which will eventually collide with the already defined symbol.
+// The line below simply tells the compiler to import the template instead of instantiating.
+template class Q_DECL_IMPORT QFutureInterface<CppEditor::Internal::SemanticInfo::Use>;
+#endif
+
 class CPPTOOLS_EXPORT CheckSymbols:
         protected CPlusPlus::ASTVisitor,
         public QRunnable,

src/plugins/cpptools/cppcodemodelsettingspage.cpp

@@ -44,7 +44,7 @@ CppCodeModelSettingsWidget::CppCodeModelSettingsWidget(QWidget *parent)
 {
     m_ui->setupUi(this);
 
-    m_ui->theGroupBox->setVisible(false);
+    m_ui->theGroupBox->setVisible(true);
 }
 
 CppCodeModelSettingsWidget::~CppCodeModelSettingsWidget()

src/plugins/cpptools/cpphighlightingsupport.h

@@ -57,7 +57,8 @@ public:
         LabelUse,
         MacroUse,
         FunctionUse,
-        PseudoKeywordUse
+        PseudoKeywordUse,
+        StringUse
     };
 
 public: