Replace clear_hook_in_cleanup with scoped_restore_hook_in

This removes clear_hook_in_cleanup in favor of a scoped_restore-like
class.  scoped_restore itself can't be used because hook_in is a
bitfield.

ChangeLog
2017-09-11  Tom Tromey  <tom@tromey.com>

	* cli/cli-script.c (class scoped_restore_hook_in): New.
	(clear_hook_in_cleanup): Remove.
	(execute_cmd_pre_hook, execute_cmd_post_hook): Use
	scoped_restore_hook_in.

gdb/ChangeLog

@@ -1,3 +1,10 @@
+2017-09-11  Tom Tromey  <tom@tromey.com>
+
+	* cli/cli-script.c (class scoped_restore_hook_in): New.
+	(clear_hook_in_cleanup): Remove.
+	(execute_cmd_pre_hook, execute_cmd_post_hook): Use
+	scoped_restore_hook_in.
+
 2017-09-11  Tom Tromey  <tom@tromey.com>
 
 	* cli/cli-script.c (restore_interp): Remove.

gdb/cli/cli-script.c

@@ -340,23 +340,36 @@ print_command_lines (struct ui_out *uiout, struct command_line *cmd,
 
 /* Handle pre-post hooks.  */
 
-static void
+class scoped_restore_hook_in
-clear_hook_in_cleanup (void *data)
 {
-  struct cmd_list_element *c = (struct cmd_list_element *) data;
+public:
 
-  c->hook_in = 0; /* Allow hook to work again once it is complete.  */
+  scoped_restore_hook_in (struct cmd_list_element *c)
-}
+    : m_cmd (c)
+  {
+  }
+
+  ~scoped_restore_hook_in ()
+  {
+    m_cmd->hook_in = 0;
+  }
+
+  scoped_restore_hook_in (const scoped_restore_hook_in &) = delete;
+  scoped_restore_hook_in &operator= (const scoped_restore_hook_in &) = delete;
+
+private:
+
+  struct cmd_list_element *m_cmd;
+};
 
 void
 execute_cmd_pre_hook (struct cmd_list_element *c)
 {
   if ((c->hook_pre) && (!c->hook_in))
     {
-      struct cleanup *cleanups = make_cleanup (clear_hook_in_cleanup, c);
+      scoped_restore_hook_in restore_hook (c);
       c->hook_in = 1; /* Prevent recursive hooking.  */
       execute_user_command (c->hook_pre, (char *) 0);
-      do_cleanups (cleanups);
     }
 }
 
@@ -365,11 +378,9 @@ execute_cmd_post_hook (struct cmd_list_element *c)
 {
   if ((c->hook_post) && (!c->hook_in))
     {
-      struct cleanup *cleanups = make_cleanup (clear_hook_in_cleanup, c);
+      scoped_restore_hook_in restore_hook (c);
-
       c->hook_in = 1; /* Prevent recursive hooking.  */
       execute_user_command (c->hook_post, (char *) 0);
-      do_cleanups (cleanups);
     }
 }