Florian Weimer <fweimer@redhat.com> writes:

> * Sam James:
>
>> It's fine if you leave this out, but consider mentioning the common
>> pitfall of autoconf projects not including config.h consistently before
>> all inclues. We could also mention AC_USE_SYSTEM_EXTENSIONS.
>
> I added: 
>
> “
> Alternatively, projects using using Autoconf
> could enable <code>AC_USE_SYSTEM_EXTENSIONS</code>.
> ”
>
> <config.h> inclusion is a larger issue, I think, best addressed by
> future diagnostics.

OK, works for me. We should discuss some options for the latter at some
point though (I think we could do it for libc cases where it matters for
LFS at least) but that's for another time.

>
>>> +<p>
>>> +When building library code on GNU systems, it was possible to call
>>> +undefined (not just undeclared) functions and still run other code in
>>> +the library, particularly if ELF lazy binding was used.  Only
>>> +executing the undefined function call would result in a lazy binding
>>> +error and program crash.
>>
>> Maybe explicitly refer to the bfd linker's relaxed behaviour so it
>> sounds less mysterious.
>
> Like this?
>
> “
> <p>
> When building library code on GNU systems,
> <a href="https://sourceware.org/binutils/docs-2.42/ld/Options.html#index-_002d_002dallow_002dshlib_002dundefined">it was possible to call
>   undefined (not just undeclared) functions</a>
> and still run other code in the library, particularly if ELF lazy binding
> was used.  Only executing the undefined function call would result in a
> lazy binding error and program crash.
> ”

Sounds good, thanks.

>
> Thanks,
> Florian

best,
sam