macos-xcode-cmake build fails with --std=c++17 SOLVED

[pdv]

On 13/11/2020 17:14, Kornel Benko wrote:
> Am Fri, 13 Nov 2020 17:04:18 +0100
> schrieb Kornel Benko <kornel at lyx.org>:
> 
>> Am Fri, 13 Nov 2020 15:27:36 +0100
>> schrieb pdv <pdvisschere at edpnet.be>:
>>
>>> I suppose HAVE_DEF_MAKE_UNIQUE should have been set to one but it wasn't.
>>> Removing HAVE_DEF_MAKE_UNIQUE from cmake's cache didn't help.
>>> The check_cxx_source_compiles() in ConfigureChecks.cmake was never
>>> executed and HAVE_DEF_MAKE_UNIQUE was never set.
>>>
>>> In the end I started from scratch and then the check ran and
>>> HAVE_DEF_MAKE_UNIQUE=1.
>>>
>>> P. De Visschere
>>
>> You should remove CMakeCache.txt, so that cmake is forced to recheck everything.
>>
>> It can also be that while checking, some other header files are used than at compile
>> time. Possible are also different compiler settings.
>>
>> 	Kornel
> 
> I had a similar problem with some left-over header files in the _build_ directory.
> So starting from scratch has to mean 'with empty build dir'.
> 
> 	Kornel
> 
> 

Yes, that's what I did: out-of-source build in an empty dir.

But I found out that this was not really needed: when emptying 
cmakecache.txt as much as possible (removing all 'internal cache 
entries' and 'external cache entries' generated by cmake) the problem is 
also solved.
In this way I could have saved my manual settings.

P. De Visschere