[rfc/testsuite/mi] use gdb_get_line_number

[Andrew Cagney]

> Here is a draft patch for gdb.mi/mi-break.exp to use
> gdb_get_line_number.
> 
> It works, but that's beside the point.  I'm looking for the right style.
> So this is RFC, not RFA.
> 
> Some questions:
> 
> . there are a lot of line_* variables.  how would you like me to name
>   them and manage them?
> 
> . some of the test names have line numbers embedded in them:
> 
>     "insert temp breakpoint at basics.c:15 (callee3)"
> 
>   this is now
> 
>     "insert temp breakpoint at basics.c:$line_callee3 (callee3)"
> 
>   so the name floats around as basics.c changes.  That is, I just
>   did the simple stupid substitution.  What would you really like for
>   test names like this?

Yea, not really. basics.c:callee3 && basics.callee3.prolog?


> + # Locate line numbers in basics.c.
> + set line_callee4        [expr [gdb_get_line_number "callee4 ("]]
> + set line_callee4_plus_2 [expr [gdb_get_line_number "callee4 ("] + 2]

I'm wondering if the latter should be called:

	line_callee4_past_prologue

(that specific name is bad but I think the intent is clear) so it's 
clear that it is past the callee4's prologu.

Andrew