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/cmakeprojectmanager/tealeafreader.cpp

@@ -384,7 +384,7 @@ void TeaLeafReader::updateCodeModel(CppTools::RawProjectParts &rpps)
         cxxProjectFlags.commandLineFlags = cxxflags;
         rpp.setFlagsForCxx(cxxProjectFlags);
 
-        rpp.setDefines(cbt.defines);
+        rpp.setMacros(cbt.macros);
         rpp.setDisplayName(cbt.title);
         rpp.setFiles(transform(cbt.files, [](const FileName &fn) { return fn.toString(); }));