[discuss] Support for reverse-execution

[Michael Snyder]

 >>     (gdb) reverse-step
 >>     # reverse-stepi once (or until we leave the *current* line)
 >
 > BTW, this bit is a little more complicated, because we might go
 > to another frame.  So we might have to do some reverse-finish's
 > stacked in there.

Absolutely -- I just wanted to focus on the one point.

 > I think infrun will need some serious cleaning
 > up to pull this off.

infrun *always* needs serious cleaning up.   ;-)

Seriously, though, we'll have to add some new state,
but I think it's doable without major rewriting.