[PATCH] bfd: fix string table generation for XCOFF64 .debug section

[CHIGOT, CLEMENT]

Hi Nick

>> String table inside XCOFF64 .debug section needs a 4-byte length field
>> instead of a 2-byte length like on XCOFF32.
>
> I am a little bit concerned with this part of the patch:
>
>   +  if (strcmp (bfd_get_target (abfd), "aix5coff64-rs6000") == 0
>   +      || strcmp (bfd_get_target (abfd), "aixcoff64-rs6000") == 0)
>   +    isxcoff64 = true;
>
> Since it is not clear to me that those are the only two valid target
> strings that will need this special treatment.  It would be better I
> feel to use some information inherent to the bfd itself.   For example:
> 
>    isxcoff64 = bfd_coff_debug_string_prefix_length (abfd) == 4;

I wasn't aware about that. But yeah, that's clearly what I want to do and 
it works, I've checked

Thanks, 
Clément