Missing 12 MFCs

[David Cross]

There are a set of commits in head that have not been pulled into the
stable/12 branch.  Many of these are marked as MFC (and are quite old).

It would be fantastic if they made it into 12.1.

All of these I am currently running against 12.0-RELEASE across multiple
environments (i386, amd64 native, amd64 emulated) without any issues and
have been for months.  They apply ALMOST entirely cleanly to 12.0-RELEASE
(there was a problem with a manpage and the date modified, and application
to a file that was removed (and thus was safe to just delete the .rej file(

ASLR/Hardening related:

r340186
r341429   (yes, I realize this undoes the previous one, but it sets the up
files for later patches to apply cleanly)
r344179
r344180
r344181
r344182
r344189
r344211
r345489
r345490
r345778
r345625


EFI Related:

r344839

Thanks!