ppc patch queue for 2018-03-19 This pull request supersedes the one for 2018-03-15. The only difference is one patch is removed, since it exposed some code which triggers ubsan warnings. Here's the set of accumulated patches now that we're into soft freeze. I've split new functionality into a ppc-for-2.13 branch, so this only has bugfixes. Well.. and a couple of simple cleanups to make bugfixes easier, some test improvements and a trivial change to make command line options more obvious. I think those are all acceptable for soft freeze.