readline fix for rl_undo_list pointer aliasing; arith command sets word_top

tests/func5.sub

@@ -0,0 +1,38 @@
+#   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/>.
+#
+
+function a=2
+{
+	printf "FUNCNAME: %s\n" $FUNCNAME
+}
+
+function 11111
+{
+	printf "FUNCNAME: %s\n" $FUNCNAME
+}
+
+declare -f
+set -o posix
+declare -f
+set +o posix
+
+a\=2
+
+break()
+{
+	echo FUNCNAME: $FUNCNAME
+}
+
+type break
+\break