[commit] Add add_setshow_enum_cmd, use in mips

[Eli Zaretskii]

> Date: Sun, 31 Oct 2004 18:01:30 -0500
> From: Andrew Cagney <cagney@gnu.org>
> Cc: gdb-patches@sources.redhat.com
> 
> The missing add_setshow_enum_cmd both goes with, and is consistent, with 
> the existing add_setshow zinteger, boolean, auto_boolean, filename, 
> string, uinteger command functions

I didn't say the patch was unreasonable, just that it should have been
an RFA, since it is by no means ``obvious''.

What about documenting the function?