[src/trunk]: src Add note for GCC 8 builds (see PR 54644)

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

details:   https://anonhg.NetBSD.org/src/rev/b6a328bf93e0
branches:  trunk
changeset: 460441:b6a328bf93e0
user:      martin <martin%NetBSD.org@localhost>
date:      Wed Oct 23 16:26:42 2019 +0000

description:
Add note for GCC 8 builds (see PR 54644)

diffstat:

 UPDATING |  10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diffs (24 lines):

diff -r 334221efdae5 -r b6a328bf93e0 UPDATING
--- a/UPDATING  Wed Oct 23 14:45:38 2019 +0000
+++ b/UPDATING  Wed Oct 23 16:26:42 2019 +0000
@@ -1,4 +1,4 @@
-$NetBSD: UPDATING,v 1.303 2019/10/01 09:36:56 mrg Exp $
+$NetBSD: UPDATING,v 1.304 2019/10/23 16:26:42 martin Exp $
 
 This file (UPDATING) is intended to be a brief reference to recent
 changes that might cause problems in the build process, and a guide for
@@ -19,6 +19,14 @@
 Recent changes:
 ^^^^^^^^^^^^^^^
 
+20191022:
+       Ports amd64 and aarch64 switched to GCC 8.3 by default.
+       In-place ("expert mode", build.sh -E) builds are not supported
+       when going from a GCC 7 userland to GCC 8. Do a regular
+       build to a different DESTDIR (or preferably: build.sh -U) at least
+       once and install sets, or download compt.{tar.xz,tgz} from the
+       daily builds and install that before doing the next in-place build.
+
 20191001:
 
        GCC 8.3 was imported.  Builds of src/tools/gcc may fail if