From: Tom Lane <tgl@sss.pgh.pa.us>
To: James Hilliard <james.hilliard1@gmail.com>
cc: pgsql-hackers@lists.postgresql.org,
        Sergey Shinderuk <s.shinderuk@postgrespro.ru>,
        Thomas Munro <thomas.munro@gmail.com>
Subject: Re: [PATCH 1/1] Fix detection of pwritev support for OSX.
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References: <20210119111625.20435-1-james.hilliard1@gmail.com>
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Comments: In-reply-to James Hilliard <james.hilliard1@gmail.com>
	message dated "Tue, 19 Jan 2021 08:36:49 -0700"
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Date: Tue, 19 Jan 2021 10:57:25 -0500
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James Hilliard <james.hilliard1@gmail.com> writes:
> On Tue, Jan 19, 2021 at 8:27 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> 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,

It worked for me and for Sergey, so we need to figure out what's different
about your setup.  What do you get from "xcrun --show-sdk-path" and
"xcrun --sdk macosx --show-sdk-path"?  What have you got under
/Library/Developer/CommandLineTools/SDKs ?

> 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 don't think I believe that argument.  As a counterexample, supposing
that somebody were intentionally cross-compiling on an older OSX platform
but using a newer SDK, shouldn't they get an executable suited to the
SDK's target version?

(I realize that Apple thinks we ought to handle that through run-time
not compile-time adaptation, but I have no interest in going there.)

			regards, tom lane