[src/trunk]: src/doc Improve documentation for BUILDID.

[apb <apb%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/2c5c5411d02e
branches:  trunk
changeset: 796695:2c5c5411d02e
user:      apb <apb%NetBSD.org@localhost>
date:      Sat Jun 14 12:20:17 2014 +0000

description:
Improve documentation for BUILDID.

diffstat:

 doc/BUILDING.mdoc |  10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diffs (36 lines):

diff -r 298155e5ff44 -r 2c5c5411d02e doc/BUILDING.mdoc
--- a/doc/BUILDING.mdoc Sat Jun 14 11:52:42 2014 +0000
+++ b/doc/BUILDING.mdoc Sat Jun 14 12:20:17 2014 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: BUILDING.mdoc,v 1.99 2014/05/21 13:11:25 wiz Exp $
+.\"    $NetBSD: BUILDING.mdoc,v 1.100 2014/06/14 12:20:17 apb Exp $
 .\"
 .\" Copyright (c) 2001-2011 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -33,7 +33,7 @@
 .\" Toolchain prefix for commands
 .ds toolprefix nb
 .
-.Dd November 8, 2012
+.Dd June 14, 2014
 .Dt BUILDING 8
 .Os NetBSD
 .
@@ -339,11 +339,17 @@
 .
 .It Sy BUILDID
 Identifier for the build.
+If set, this should be a short string that is suitable for use as
+part of a file or directory name.
 The identifier will be appended to
 object directory names, and can be consulted in the
 .Xr make 1
 configuration file in order to set additional build parameters,
 such as compiler flags.
+It will also be used as part of the kernel version string,
+which can be printed by
+.Dq Li uname \-v .
+.DFLTu
 .
 .It Sy BUILDSEED
 GCC uses random numbers when compiling C++ code.