commands: allow <cmd>_aliases[] to be const

Commands with aliases define an array of alias strings such as:

  static const char *<cmd>_aliases[] = { "<alias1>", NULL};

Although the elements are of type `const char *`, the elements
themselves are not `const`-qualified.  If the array is declared as:

  static const char * const <cmd>_aliases[] = { "<alias1>", NULL};

then the compiler warns about const qualifiers being discarded.  This is
because the `aliases` member of `struct command` is declared as `const
char *aliases;`.

Change the declaration of the `aliases` member of `struct command` to
`const char * const *aliases;` so that it can point to a `const` array
of `const char *`.  Also change the declaration of the `aliases`
variable in `register_command()` to avoid unnecessary type casts.

Signed-off-by: Ian Abbott <[email protected]>
Signed-off-by: Sascha Hauer <[email protected]>

common/command.c

@@ -104,7 +104,7 @@ int register_command(struct command *cmd)
 	list_add_sort(&cmd->list, &command_list, compare);
 
 	if (cmd->aliases) {
-		char **aliases = (char**)cmd->aliases;
+		const char * const *aliases = cmd->aliases;
 		while(*aliases) {
 			struct command *c = xzalloc(sizeof(struct command));
 

include/command.h

@@ -40,7 +40,7 @@ struct string_list;
  */
 struct command {
 	const char	*name;		/* Command Name			*/
-	const char	**aliases;
+	const char	* const *aliases;
 					/* Implementation function	*/
 	int		(*cmd)(int, char *[]);
 	int		(*complete)(struct string_list *sl, char *instr);