GenericProjectManager: Support framework paths

Rather than adding yet another meta file, we use the .includes file with
a special line prefix.

Fixes: QTCREATORBUG-20099
Change-Id: I494e0143b8e0f1f8828a56d7487b2201f1680337
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/genericprojectmanager/genericproject.h

@@ -25,6 +25,7 @@
 
 #pragma once
 
+#include <projectexplorer/headerpath.h>
 #include <projectexplorer/project.h>
 #include <utils/fileutils.h>
 
@@ -82,7 +83,7 @@ private:
     QStringList m_files;
     QHash<QString, QString> m_rawListEntries;
     QStringList m_rawProjectIncludePaths;
-    QStringList m_projectIncludePaths;
+    ProjectExplorer::HeaderPaths m_projectIncludePaths;
     QStringList m_cxxflags;
     QStringList m_cflags;