ProjectPart: Add callGroupId

Do not rely on the projectfile being unique anymore.

Change-Id: I52e63b3ac8aeca43ef70af1d59d1d8612bd3540e
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/cpptools/projectpart.h

@@ -108,6 +108,7 @@ public:
     int projectFileLine = -1;
     int projectFileColumn = -1;
     QString projectConfigFile; // currently only used by the Generic Project Manager
+    QString callGroupId;
 
     ProjectFiles files;