gdb: remove cmd_list_element::pre_show_hook

This is unused, remove it.

gdb/ChangeLog:

	* cli/cli-decode.h (struct cmd_list_element) <pre_show_hook>:
	Remove.
	* cli/cli-setshow.c (do_show_command): Adjust.

Change-Id: Ib9cd79d842550392b062309e1e5c079ad5d7571a

gdb/ChangeLog

@@ -1,3 +1,9 @@
+2021-05-13  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* cli/cli-decode.h (struct cmd_list_element) <pre_show_hook>:
+	Remove.
+	* cli/cli-setshow.c (do_show_command): Adjust.
+
 2021-05-13  Luis Machado  <luis.machado@linaro.org>
 
 	* arch/aarch64-mte-linux.c (aarch64_mte_get_tag_granules): Don't

gdb/cli/cli-decode.h

@@ -187,10 +187,6 @@ struct cmd_list_element
   /* If this command is deprecated, this is the replacement name.  */
   const char *replacement = nullptr;
 
-  /* If this command represents a show command, then this function
-     is called before the variable's value is examined.  */
-  void (*pre_show_hook) (struct cmd_list_element *c) = nullptr;
-
   /* Hook for another command to be executed before this command.  */
   struct cmd_list_element *hook_pre = nullptr;
 

gdb/cli/cli-setshow.c

@@ -708,10 +708,6 @@ do_show_command (const char *arg, int from_tty, struct cmd_list_element *c)
 
   gdb_assert (c->type == show_cmd);
 
-  /* Possibly call the pre hook.  */
-  if (c->pre_show_hook)
-    (c->pre_show_hook) (c);
-
   std::string val = get_setshow_command_value_string (c);
 
   /* FIXME: cagney/2005-02-10: There should be MI and CLI specific