RFA: fix gdb.texinfo for Texinfo 5.0

[Eli Zaretskii]

> From: Tom Tromey <tromey@redhat.com>
> Date: Thu, 21 Feb 2013 08:10:53 -0700
> 
> I tried Texinfo 5.0 on gdb.texinfo today, and it gave a number of
> warnings.
> 
> These fell into two major categories: first, we were using @table
> without any @items; and second, we were using @item without an argument.
> 
> The fix for the first problem is to just remove the @table.
> There's no need for it.

It's possible that someone used this trick to get the text indented.
All of those instances are around @defXXX directives, so perhaps
someone didn't like how functions/methods/etc. look unless indented.
But if you are satisfied by the results of removing @table in those
cases, that's fine by me.

> The fix for the second was to use @w{} as the argument to @item.

Yes, Texinfo 5.0 replaced one ugly kludge with another, sigh.
(We left the @item empty because we wanted `' in the manual, by virtue
of "@table @samp".)

> This patch fixes all the problems.

Thanks!

> Tested by rebuilding with makeinfo 5.0 and makeinfo 4.13.
> 
> Ok?

Yes, thanks.

P.S.  I recommend everybody not to use makeinfo 5 yet, since it's
dog-slow.  I renamed it to 'makeinfo5' and keep the old v4.13a
executable around, because it is 30 times faster, and that really
shows when processing such a large manual.