FYI,

Keep insight building.  There is now get_selected_frame() but that 
throws an error when there isn't a frame.

(NB, there is also a bug lurking here.  When the inferior has 
stack/registers, GDB should always create a frame.  It some times 
doesn't - instead it throws an error.  The fix is to catch the error and 
create a fake frame.

While at it, I took the oportunity to clean up a few get_frame_pc()s and 
find_frame_sal()s.

committed,
Andrew