Kernel prepatch 6.8-rc1

The 6.8-rc1 kernel prepatch is out for
testing.

So this wasn't the most pleasant merge window, but most of the
unpleasantness was entirely unrelated to the code base and almost
entirely related to nasty weather. Just a few technical
hiccups. And after a very big 6.7 release, 6.8 looks to actually be
smaller than average, although not really all that significantly
so.