[CMake] ZERO_CHECK generation and Xcode

[Gregor Jasny]

On 3/29/17 10:15 PM, Steven Velez wrote:
> I do have a pretty large project with around 142 targets.
> 
> Another characteristic of note, and which I noticed while investigating
> this is that our project suffers from
> https://gitlab.kitware.com/cmake/cmake/issues/14297, and I think it is
> because we have "project" declarations underneath the top-level... so
> ZERO_CHECK builds concurrently with other targets.

Oh boy. Thanks for pointing this out.

> I did create an xcode scheme that builds a smaller set of targets (6), and
> made sure that they all depended on ZERO_CHECK, and then ZERO_CHECK ran by
> itself, and it appeared that after a single test, it did manage to complete
> updating so that it did not run on subsequent invocations.

I'll have a look.