MFC r284527,r284528,r284608,r285219,r291166,r291167:

MFC r284527,r284528,r284608,r285219,r291166,r291167:

r284527 (by imp):

Update style.9 to reflect consensus on developer's mailing list
allowing redundant braces.

Differential Revision: https://reviews.freebsd.org/D2842

r284528 (by imp):

Bump date.

Submitted by: Xin Li

r284608 (by imp):

Back out contested change until dispute is resolved. This proved to be
more contentious than I expected.

r285219 (by imp):

The results of the vote are in. This reflects that vote. Single
line statements inside of braces is recognized as an acceptable
style.
	http://reviews.freebsd.org/V3
As always, this isn't license for wholesale change, etc.

r291166:

Recommend cc -Wall instead of gcc -Wall

r291167:

Bump .Dd