Implement the -a option to bump the annotation_level. This improves
the Emacs gud behaviour. You can now supply the following function
(defun gud-gdb-massage-args (file args) (cons "-a" args))
(e.g. by evaluating it from the *scratch* buffer) and get the normal
jump to the source window when browsing the stack.
We should probably eventually supply our own kgdb submode to gud.el.
fa632bb17f