bug#40741: Cannot build 27.0.91 on macOS 10.6.4

[Tak Kunihiro]

>>>>> The second pretest for what will be the 27.1 release of Emacs (the
>>>>> extensible text editor) is available at
>>>>> 
>>>>>  https://alpha.gnu.org/gnu/emacs/pretest/emacs-27.0.91.tar.xz
>>>> 
>>>> I cannot build emacs 27.0.91 on macOS 10.6.4 with Xcode 11.3.1.
>>>> I can build emacs 26.3 on the same environment.
>>> 
>>> I believe this is a duplicate of bug#36172, as linked on that page.
>>> 
>>> Are you using any flags with configure?
>> 
>> I saw suggestion on bug#36172 to call following command.  That did not
>> change situation.
>> 
>>  sudo xcode-select -s /Applications/Xcode.app
>> 
>> I call both `./configure' and `make' without any options.
> 
> On difference computer with macOS 10.6.4, I confirm that I could build
> emacs 27.0.91.  Thus I think this is my local problem.

I uninstall Xcode 11.3.1 and related files.
Then install Xcode 11.3.1 again.  Now I can build emacs 27.0.91.

I have upgraded Xcode several times on the past.  I suppose piles
of upgrade brought glitches.