fixes for several bugs found via fuzzing: overflow in $'...' hex expansion; fix for accessing freed memory when reading input from stdin and using multiple redirections to stdin; fix for pointer aliasing problem after a syntax error while executing a command string

tests/history.right

@@ -403,3 +403,39 @@ EOF
 
 
     5  echo three
+	history10.sub
+    1  echo first
+    2  echo one
+    3  echo two
+    4  echo three
+    5  echo x
+    6  echo y
+    7  echo z
+    8  echo last
+echo one append
+one append
+echo two append
+two append
+echo three append
+three append
+    1  echo first
+    2  echo x
+    3  echo y
+    4  echo z
+    5  echo last
+    6  echo one append
+    7  echo two append
+    8  echo three append
+edit
+echo edit append
+edit append
+    1  echo first
+    2  echo x
+    3  echo y
+    4  echo z
+    5  echo last
+    6  echo one append
+    7  echo two append
+    8  echo three append
+    9  # simulate readline edit_and_execute_command
+   10  echo edit append

tests/history.tests

@@ -137,3 +137,4 @@ test_runsub ./history6.sub
 test_runsub ./history7.sub
 test_runsub ./history8.sub
 test_runsub ./history9.sub
+test_runsub ./history10.sub

tests/history10.sub

@@ -0,0 +1,53 @@
+#
+#   Copyright 2025 Free Software Foundation, Inc.
+#
+#   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/>.
+#
+
+# basic test for fc -D
+: ${TMPDIR:=/tmp}
+
+stream()
+{
+	# something you can see
+	sed 's/$/ append/' < $1 >$TMPF && mv $TMPF $1
+	rm -f $TMPF
+}
+
+HISTFILE=$TMPDIR/fchist-$BASHPID
+TMPF=$TMPDIR/fctmp-$BASHPID
+
+trap 'rm -f "$HISTFILE" "$TMPF"' 0 1 2 3 6 15
+
+cat > $HISTFILE <<EOF
+echo first
+echo one
+echo two
+echo three
+echo x
+echo y
+echo z
+echo last
+EOF
+
+set -o history
+
+history
+fc -e stream -D 2 4
+history
+
+# simulate readline edit_and_execute_command
+echo edit
+fc -e stream -D
+history