Re: Fixing AC_CHECK_DECLS to do the right thing with clang

Hi,

On 2018-11-17 23:32:47 -0500, Tom Lane wrote:
> We've seen repeated complaints about bogus build warnings when using
> "clang": it complains that strlcpy and some related library functions
> haven't been declared. Several of the buildfarm animals exhibit such
> warnings, for instance. That's because Autoconf's AC_CHECK_DECLS macro
> fails to cope with the fact that clang only generates a warning, not
> an error, for the test case that that macro uses. Noah fixed this
> in upstream autoconf several years ago:
>
> http://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=82ef7805faffa151e724aa76c245ec590d174580
>
> However, I'm beginning to despair of the Autoconf crowd ever putting
> out an official new release. Hence, I propose to apply and back-patch
> the attached, which essentially just imports Noah's fix into our
> configure script. I've verified that this does the right thing with
> Fedora 28's version of clang (clang version 6.0.1).

Seems like a good plan. The problem doesn't reproduce for me on debian
(using any version of clang), so all I can report is that at patched
build still works as it should.

- Andres