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

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).  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 ...

            regards, tom lane