Convert macros from plain QByteArray to a vector of structs

The old code model expected the macros as C++ formatted text
("#define Foo 42) but newer targets like the Clang codemodel expect key
value arguments like "-DFoo=42". So instead of parsing the text again and
again we use an abstract data description.

Task-number: QTCREATORBUG-17915
Change-Id: I0179fd13c48a581e91ee79bba9d42d501c26f19f
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/cpptools/projectinfo.h

@@ -123,7 +123,7 @@ private:
     // The members below are (re)calculated from the project parts with finish()
     ProjectPartHeaderPaths m_headerPaths;
     QSet<QString> m_sourceFiles;
-    QByteArray m_defines;
+    ProjectExplorer::Macros m_defines;
 };
 
 } // namespace CppTools