Identifying a dummy frame using a frame id

[Michael Elizabeth Chastain]

> Now, there is a little detail missing - how GDB relocate the dummy frame 
> object that contains those saved registers.  The problem is that GDB 
> can't just take the most recent one as, due to long jumps and the like, 
> it can be wrong.

I can't comment on the internal mechanism, but I know that as a user of
gdb, if something happens during a hand function call to marker2() like
gdb hitting another breakpoint or me hitting ^C, then gdb starts acting
a little drunk at that point.  So I bet that explicit save/restore of
these frames would help.

Michael C