Applying pipe fix this merge window?

[Josh Triplett]

I've been hammering on your pipe fix patch (switching to exclusive wait
queues) for a month or so, on several different systems, and I've run
into no issues with it. The patch *substantially* improves parallel
build times on large (~100 CPU) systems, both with parallel make and
with other things that use make's pipe-based jobserver.

All current distributions (including stable and long-term stable
distributions) have versions of GNU make that no longer have the
jobserver bug.

Based on that, would you consider merging the pipe fix patch in the
current merge window, giving people plenty of time to hammer on it
further?

- Josh Triplett