[rfa:symtab] deprecate inside_entry_func

[Andrew Cagney]

> 
> What Kevin and I have both repeatedly suggested, I think, is:
>   - Do not deprecate inside_entry_func; fix it if you don't like the
>     way it is implemented.  Change the implementation.
>   - Deprecate entry_func_lowpc and entry_func_highpc (there's a typo in
>     your changelog, two lowpc's) if you really want to deprecate
>     something.

Please point me at a legitimate use of this function.

Andrew