Mostly merge from master plus a few more that were still in the
stable/15.7 code base.

(cherry picked from commit 343aa7df)
(cherry picked from commit 692a8f77)
(cherry picked from commit f8b281e9)
(cherry picked from commit 8d2e334b)
(cherry picked from commit b9346703)
(cherry picked from commit 418b13af)
(cherry picked from commit b235235d)
(cherry picked from commit e259289f)
(cherry picked from commit 68fed4c9)
(cherry picked from commit 8757d000)
(cherry picked from commit 33394bdc)
(cherry picked from commit 8cccf2e8)
(cherry picked from commit eb29c782)
(cherry picked from commit 3fcda571)
(cherry picked from commit 4ff0b327)