CMake: Fix parsing of C++ defines

Partially revert 20cfccd753 that somehow
assumed that compiler flags would also include the defines.

See comment on
Task-number: QTCREATORBUG-3922

Change-Id: Ic7cb9dfa33f53fde9302f38018102c15cb12f83d
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/cmakeprojectmanager/cmakeproject.h

@@ -162,6 +162,7 @@ public:
     QList<ProjectExplorer::FileNode *> cmakeFileList();
     QStringList includeFiles();
     QList<CMakeBuildTarget> buildTargets();
+    QByteArray defines() const;
     QString projectName() const;
     QString compilerName() const;
     bool hasCMakeFiles();
@@ -188,6 +189,7 @@ private:
     bool m_parsingCmakeUnit;
     QStringList m_includeFiles;
     QStringList m_compilerOptions;
+    QByteArray m_defines;
 
     CMakeBuildTarget m_buildTarget;
     QList<CMakeBuildTarget> m_buildTargets;