MFC r261261: Restore the Nx macro.

PR:		186205
Submitted by:	naddy
MFC: Update link to vendor import instructions
MFC: Merge sendmail 8.14.8
MFC: Add new sendmail 8.14.8 file
MFC: Remove local FreeBSD workaround now that upstream project has a better fix.
MFC: Update for sendmail 8.14.8 import
MFC: Add missing svn:keywords property to new files
MFC: Minor changes to force commit these files so new freebsd*.cf files are
     built to use the new sendmail-8.14.8/cf tree.
MFC: Note merge of sendmail 8.14.8.
MFC r260883:
Remove unneeded and dangerous assignment.  It would probably cause NULL
refererence panic if compiler not optimize it out.
[automated] Merge in upstream-github/stable/9