Re: [PATCH 1/1] Fix compilation on mac with Xcode >= 11.4.

I wrote:
> However ... it then occurred to me to blow away my ccache and accache,
> and after rebuilding from scratch, everything's fine.  So, are you
> using ccache?

Oh, scratch that, I fat-fingered the experiment somehow.  The issue
is still there.  Still, I'm hesitant to apply the fix you suggest,
because of the law of unintended consequences.  In particular, I'm
afraid that using -isysroot in the link step might result in executables
that are bound to that sysroot and will not work if it's not there
--- thus causing a problem for packagers trying to distribute PG
to non-developers.

We had a great deal of trouble in the initial experiments with
-isysroot, cf

https://www.postgresql.org/message-id/flat/20840.1537850987%40sss.pgh.pa.us

so I'm not that eager to mess with it.  I'm inclined to think that
this is more a case of "Apple broke ABI and they ought to fix that".

			regards, tom lane