Besides the fact that compiling for an older SDK increases the number of versions where the build works, I believe that Sebastian encountered problems with the compiler for the newer versions that were available at the time he put together the build system together.  It's been a while, but if I recall correctly, someone brought the issue to Apple's attention and it's been fixed in newer releases.  So, it may be that if you update to something "new enough" that that will fix this issue without breaking everything.

Best,
Erich

On Mon, Mar 23, 2020, 11:11 PM Alistair Leslie-Hughes <leslie_alistair@hotmail.com> wrote:
Hi Chip

On 24/3/20 4:01 pm, Chip Davis wrote:
> March 23, 2020 11:08 PM, "Alistair Leslie-Hughes" <leslie_alistair@hotmail.com> wrote:
>
>> This stops a compile on the macos.
>
> Is someone actually using an old (10.9 or lower) SDK to build this? (fstatat(2) was added in Mac OS 10.10.)

Yes, the build box uses an older SDK.

Maybe Sebastian or Michael can comment, if it can be updated?

Alistair.