Re: [PATCH 1/1] Fix detection of pwritev support for OSX.

On Tue, Jan 19, 2021 at 8:27 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> James Hilliard <james.hilliard1@gmail.com> writes:
> > Fixes:
> > gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla -Wendif-labels
-Wmissing-format-attribute-Wformat-security -fno-strict-aliasing -fwrapv -Wno-unused-command-line-argument -O2
-I../../../../src/include -isysroot
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.1.sdk   -c -o fd.o fd.c 
> > fd.c:3661:10: warning: 'pwritev' is only available on macOS 11.0 or newer [-Wunguarded-availability-new]
>
> We already dealt with that by not selecting an SDK newer than the
> underlying OS (see 4823621db).
Tried that, doesn't work, not even sure how it could possibly fix this
issue at all,
this can not be fixed properly by selecting a specific SDK version
alone, it's the
symbols valid for a specific target deployment version that matters here.
> I do not believe that your proposal
> is more reliable than that approach, and it's surely uglier.  Are
> we really going to abandon Autoconf's built-in checking method every
> time Apple adds an API they should have had ten years ago?  If so,
> you forgot preadv ...
I didn't run into an issue there for some reason...but this was the cleanest fix
I could come up with that seemed to work.
>
>                         regards, tom lane