It is a trifle irritating, particularly in view of Doctrine which demands warning-free compilation, but can I suggest a metasolution? What would be really useful would be an instrumented version of the compiler which produced a report of all libraries/packages producing this warning which could be collated and fixed as a single exercise.
After all, each var -> out is a change which, if unsuccessful, will generate a compile error indicating that it should be rolled back.
MarkMLl