A+C: Thiago Fransosi Farina (individual CLA)

Generated by a+c.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://codereview.appspot.com/125960043
dist: Make vaddn private to buf.c

This function does not have a declaration/prototype in a.h, and it is used only
in buf.c, so it is local to it and thus can be marked as private by adding
'static' to it.

LGTM=iant
R=rsc, iant
CC=golang-codereviews
https://codereview.appspot.com/122300043

Committer: Ian Lance Taylor <iant@golang.org>