change to readline callback signal handling; fix message when popping shell function context; handle new terminating signals inside terminating signal handler; fix to pattern substitution with null replacement and null string; fix to alias expansion when we get a SIGINT while entering a command substitution in an interactive shell

tests/extglob.tests

@@ -379,6 +379,11 @@ shopt -u globstar
 # in the right place
 builtin cd "$MYDIR"
 
+# seg fault in bash-5.2
+foo=
+foo=${foo/#*([.])}
+unset foo
+
 ${THIS_SH} ./extglob1.sub
 ${THIS_SH} ./extglob1a.sub
 ${THIS_SH} ./extglob3.sub