RFA: make add_setshow_cmd public

[Tom Tromey]

>>>>> "Andrew" == Andrew Cagney <ac131313@cygnus.com> writes:

Andrew> Can the public version return void?

I looked.  There is this code in cli-cmds.c that uses the return value:

    set_verbose (NULL, 0, c);

This whole joke function is pretty stale though and could be removed.
IMHO.

Also from infcmd.c:

    set_cmd_completer (c, filename_completer);

All other uses (that I've run into so far) are for deprecation.
Right now the straightforward translation breaks these uses.
Any preferences here?

Tom