D7: editor multi-cursor support

Add secondary_cursors field to Editor with insert_char_multi,
delete_back_multi, delete_forward_multi methods. Right-to-left
processing ensures position shifts don't corrupt earlier insertions.

7 new tests: add/clear, all_positions, insert, delete_back,
delete_forward, unicode, duplicate-add.

local/recipes/tools/diffutils/source/gnulib-tests/test-version-etc.sh

@@ -0,0 +1,43 @@
+#! /bin/sh
+# Test suite for version-etc.
+# Copyright (C) 2009-2017 Free Software Foundation, Inc.
+# This file is part of the GNUlib Library.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+TMP=ve-expected.tmp
+LC_ALL=C
+export LC_ALL
+ERR=0
+
+cat > $TMP <<EOT
+test-version-etc (PROJECT) VERSION
+COPYRIGHT Free Software Foundation, Inc.
+License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
+
+Written by Sergey Poznyakoff and Eric Blake.
+EOT
+
+./test-version-etc${EXEEXT} --version |
+ sed '1s/test-version-etc (.*) .*/test-version-etc (PROJECT) VERSION/
+      /^Packaged by/d
+      2,3 s/Copyright (C) [0-9]\{4,4\}/COPYRIGHT/' |
+ tr -d '\015' |
+ diff -c $TMP - || ERR=1
+
+rm $TMP
+
+exit $ERR