[PATCH] No resuming while tfinding

[Stan Shebs]

Tom Tromey wrote:
> Does return_command also need to call ensure_not_tfind_mode?
>   
It seemed less necessary, because it doesn't resume, it just scribbles 
on the stack - in tfind mode the target kicks it back with write errors.

The previous discussion has gotten me to wondering whether it would be a 
good idea to allow the user to write into a trace buffer.  While it 
sounds crazy at first, it can make sense for the same reasons that it 
does in a live target; you have a hypothesis about how an expression 
calculates out, stuff the hypothesized value in memory, and print the 
expression.

It's a little more farfetched that return would be useful if writing 
worked; if you had collected enough stack, you would see a backtrace 
displayed as if the return had been done, but since you can't resume, 
the exercise seems pointless.

Stan