two minor fixes to glibc wiki FAQ

[Florian Weimer]

* Jones Syue 薛懷宗:

>>> Should we remove this line "(there are exceptions, e.g. __ivaliduser)"?
>>> Found this wiki faq is inconsistent with my result when compiling lpr
>>> source code with recent glibc version and got a link error like this:
>>>
>>> /path/to/ld: lpd.o: in function `chkhost':
>>> lpd.c:(.text+0x1059): undefined reference to `__ivaliduser'
>>
>> Right, __register_atfork is probably a good long-term replacement.
>
> Looks good to me! Replace 'e.g. __ivaliduser' with 'e.g. __register_atfork'
> is good.
>
>> Linking to
>> <https://www.kernel.org/doc/html/latest/kbuild/headers_install.html>
>> perhaps makes more sense?
>
> This link looks good to me! Thank you Florian :)

I've updated the wiki page.

Thanks,
Florian