RFA: manual updates for c++

[Eli Zaretskii]

> From: Tom Tromey <tromey@redhat.com>
> Date: Thu, 10 Nov 2011 11:45:16 -0700
> 
> This needs a doc review.
> 
> While looking at the manual, I noticed some outdated advice and some
> missing information about C++ debugging.  This patch fixes the problems.

Thank you for doing this.

> Both -gstabs+ and -gdwarf-2 are obsolete nowadays

On most platforms, but not on all of them.  It's true that -gdwarf-2
is the default, though.

> +                                               Starting with version
> +4.7, @value{NGCC} can emit macro information in a more compact format.

Why is this part important to a GDB user?

> +     Recent versions of @value{NGCC} support @option{-gdwarf-3}
> +@option{-gdwarf-4};

Should there be an "and" between the two option names?  They are
orthogonal, right?

OK with these fixed.

Thanks.