[RFA] Fix breakpoint condition that use member variables.

[Eli Zaretskii]

> From: Vladimir Prus <vladimir@codesourcery.com>
> Date: Sat, 22 Mar 2008 12:40:15 +0300
> 
> Suppose that foo.cpp:10 is a location inside member function of a class,
> and that said class has member variable i_, and that we've just started
> a program and are in main. Then:
> 
>     break foo.cpp:10 if i_ == 10
> 
> will not work, claiming that i_ does not exist. The problem is that
> lookup_symbol_aux uses value_of_this, which uses value_of_local and
> that totally ignores the block that is passed to parse_exp_1 by
> the breakpoint code and uses the block of the selected frame. Of course,
> that either does not have "this", or has wrong "this".
> 
> This patch fixes the problem by looking in the right block directly,
> and also by looking for the field in the type of "this", without
> trying to get the value.

What will happen after your patch if there's also a variable i_ in the
selected frame?