Use GPLv2+ plus exception as license for release.

Return back to GPLv2+, until the text of the exceptions is
finalized, reverting the change from 2007-07-03 and the first
part of the change from 2007-07-20.

Also:
* COPYING: Revert to GPLv2.
* COPYINGv3: New file, since some auxiliary build tools, used for
building autoconf and not installed, are GPLv3.
* Makefile.am (EXTRA_DIST): Distribute COPYINGv3.
* NEWS: Remove mention of GPLv3.
* README: Clarify situation regarding GPLv3.

Signed-off-by: Eric Blake <ebb9@byu.net>

1 files changed, 19 insertions, 0 deletions

diff --git a/README b/README
index 303b5ae0..9641812f 100644
--- a/README
+++ b/README
@@ -40,6 +40,25 @@ running `autoconf --version'.  Archives of bug-autoconf@gnu.org can be
 found in <http://lists.gnu.org/archive/html/bug-autoconf/>, and
 similarly for the other mailing lists.
 
+Licensing
+
+Autoconf is released under the General Public License (GPL).
+Additionally, Autoconf includes a licensing exception in some of its
+source files; see the respective copyright notices for how your
+project is impacted by including scripts generated by Autoconf.
+
+This version of Autoconf uses GPLv2+ plus the above-mentioned
+exceptions for its installed executables, as described in COPYING.
+Meanwhile, several source files within the Autoconf project are under
+GPLv3+, as described in COPYINGv3; these files are used for building
+and installing Autoconf, but are not present in the installed
+programs.  The entire Autoconf project will move to GPLv3+ when the
+exception statements have been reformulated in terms of the Additional
+Permissions as described in section 7 of GPLv3.
+
+For more licensing information, see
+<http://www.gnu.org/licenses/gpl-faq.html>.
+
 -----
 
 Copyright (C) 1992, 1993, 1994, 1998, 2000, 2001, 2002, 2003, 2004,