F22 System Wide Change: GCC5

[Miloslav Trmač]

> * Contingency mechanism: Revert to older gcc, mass rebuild everything again
> * Contingency deadline: Before release

This is an invasive contingency mechanism, requiring retesting a lot of functionality; the contingency deadline for this (i.e. when we need to be comfortable that the revert will not be needed, should certainly be at the usual beta freeze at the latest, if not earlier.  Invoking this contingency mechanism “before release”, say during the GA RC phase, would really not be feasible without a massive slip.
    Mirek