[PATCH v4] Add helper script for glibc debugging

[Gabriel F. T. Gomes]

On Mon, 30 Sep 2019, Gabriel F. T. Gomes wrote:

>On Fri, 27 Sep 2019, Carlos O'Donell wrote:
>
>>Would you be willing to also update:
>>https://sourceware.org/glibc/wiki/Testing/Builds
>>
>>We should suggest the new option.  
>
>Sure. I'll update it with the new instructions. :)

Now updated (https://sourceware.org/glibc/wiki/Testing/Builds#Required_gdb_setup)
I didn't add details about the available parameters to the script, as I
believe this could make the wiki obsolete with time.  Also I'm wary of
changing the section name, because of potential broken links that might
show up if the anchor is gone.