C++: add code-model support for defines-per-editor.

The UI side will come in another commit.

Change-Id: I1038a438587fe4cef70408f7f627d08837fc192d
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cpptools/cppsnapshotupdater.h

@@ -65,6 +65,7 @@ public:
     { return m_frameworkPaths; }
 
     void setUsePrecompiledHeaders(bool usePrecompiledHeaders);
+    void setEditorDefines(const QByteArray &editorDefines);
 
 private:
     void updateProjectPart();
@@ -75,6 +76,8 @@ private:
     QString m_fileInEditor;
     ProjectPart::Ptr m_projectPart;
     QByteArray m_configFile;
+    bool m_editorDefinesChangedSinceLastUpdate;
+    QByteArray m_editorDefines;
     QStringList m_includePaths;
     QStringList m_frameworkPaths;
     QStringList m_precompiledHeaders;