Android: Set ANDROID_EXTRA_LIBS scoped to the arch

The workflow for adding a library for multiple archs is not ideal, but
now a little better. The user has to go to the deploy setting for a
kit per architecture and add the right extra library.

Change-Id: I2bda6961f6f1164bdc58acd78fa3d2221977f0cf
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>

src/plugins/android/androidextralibrarylistmodel.h

@@ -68,6 +68,7 @@ private slots:
 private:
     QmakeProjectManager::QmakeProject *m_project;
     QStringList m_entries;
+    QString m_scope;
 };
 
 } // namespace Internal