[C/C++ PATCH] Implement -Wbool-compare (PR c++/62153)

[Jason Merrill]

On 08/18/2014 04:04 PM, Marek Polacek wrote:
> Unfortunately, this warning cannot be enabled by -Wall yet, because
> of a few blunders we have in the codebase.  But we really should iron out
> that soon.

Can you take care of that as well?

The patch looks good to me, but if it should be part of -Wall I want 
there to be a plan beyond "someone should fix it".  :)

Jason