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/cppmodelmanager.h

@@ -163,7 +163,7 @@ public:
     // Use this *only* for auto tests
     void setHeaderPaths(const ProjectPartHeaderPaths &headerPaths);
 
-    QByteArray definedMacros();
+    ProjectExplorer::Macros definedMacros();
 
     void enableGarbageCollector(bool enable);
 
@@ -229,7 +229,7 @@ private:
     void ensureUpdated();
     QStringList internalProjectFiles() const;
     ProjectPartHeaderPaths internalHeaderPaths() const;
-    QByteArray internalDefinedMacros() const;
+    ProjectExplorer::Macros internalDefinedMacros() const;
 
     void dumpModelManagerConfiguration(const QString &logFileId);