gdb: make add_com_alias accept target as a cmd_list_element

The alias creation functions currently accept a name to specify the
target command.  They pass this to add_alias_cmd, which needs to lookup
the target command by name.

Given that:

 - We don't support creating an alias for a command before that command
   exists.
 - We always use add_info_alias just after creating that target command,
   and therefore have access to the target command's cmd_list_element.

... change add_com_alias to accept the target command as a
cmd_list_element (other functions are done in subsequent patches).  This
ensures we don't create the alias before the target command, because you
need to get the cmd_list_element from somewhere when you call the alias
creation function.  And it avoids an unecessary command lookup.  So it
seems better to me in every aspect.

gdb/ChangeLog:

	* command.h (add_com_alias): Accept target as
	cmd_list_element.  Update callers.

Change-Id: I24bed7da57221cc77606034de3023fedac015150

1 files changed, 5 insertions, 4 deletions

diff --git a/gdb/printcmd.c b/gdb/printcmd.c
index a5c03c3..8daa87c 100644
--- a/gdb/printcmd.c
+++ b/gdb/printcmd.c
@@ -3351,10 +3351,11 @@ EXP may be preceded with /FMT, where FMT is a format letter\n\
 but no count or size letter (see \"x\" command)."),
 					      print_opts);
 
-  c = add_com ("print", class_vars, print_command, print_help.c_str ());
-  set_cmd_completer_handle_brkchars (c, print_command_completer);
-  add_com_alias ("p", "print", class_vars, 1);
-  add_com_alias ("inspect", "print", class_vars, 1);
+  cmd_list_element *print_cmd
+    = add_com ("print", class_vars, print_command, print_help.c_str ());
+  set_cmd_completer_handle_brkchars (print_cmd, print_command_completer);
+  add_com_alias ("p", print_cmd, class_vars, 1);
+  add_com_alias ("inspect", print_cmd, class_vars, 1);
 
   add_setshow_uinteger_cmd ("max-symbolic-offset", no_class,
 			    &max_symbolic_offset, _("\