Explicit Linespecs Branch Created

[Tom Tromey]

Keith> IOW, I am/was trying to avoid implementing backend gdb APIs in terms
Keith> of the command line.

Tom> I see.  Well, that does make sense.  It just seems like it will be hard
Tom> to use from the CLI.

I've been thinking about this a bit.

It seems to me that making the user interface harder to use for the sake
of implementation cleanliness (without additional factors like
scalability) is the wrong tradeoff.

Tom