segfaults with function attribute manipulations

[Grisha Levit]

A couple silly function attribute manipulations lead to situations that
result in segfaults:

$ f() { :; }; declare -Af f; declare -pf f
[ segfault ]

diff --git a/builtins/setattr.def b/builtins/setattr.def
index 251bcacb..1a828291 100644
--- a/builtins/setattr.def
+++ b/builtins/setattr.def
@@ -474,9 +474,9 @@ show_var_attributes (var, pattr, nodefs)
 #if defined (ARRAY_VARS)
   if (invisible_p (var) && (array_p (var) || assoc_p (var)))
     printf ("%s\n", var->name);
-  else if (array_p (var))
+  else if (array_p (var) && function_p (var) == 0)
     print_array_assignment (var, 0);
-  else if (assoc_p (var))
+  else if (assoc_p (var) && function_p (var) == 0)
     print_assoc_assignment (var, 0);
   else
 #endif

(Maybe the better solution would be to prevent meaningless attributes from
getting assigned to functions in the first place, but they seem harmless
otherwise).

$ f() { :; }; declare +f -f f; declare -pf f
declare -- f=" "
$ f() { :; }; declare -Af f; declare +f -f f; unset -f f
[ segfault ]

diff --git a/builtins/declare.def b/builtins/declare.def
index 7eac6f58..bc44f54c 100644
--- a/builtins/declare.def
+++ b/builtins/declare.def
@@ -558,6 +558,7 @@ restart_new_var_name:
                  else          /* declare -[fF] -[rx] name [name...] */
                    {
                      VSETATTR (var, flags_on);
+                      flags_off &= ~att_function;
                      VUNSETATTR (var, flags_off);
                    }
                }