[CMake] cmake rewrites part of -S argument depending on the current directory!

[Brad King]

On 5/30/19 1:25 PM, Marc Herbert wrote:
> I suspect the behaviour I described is also considered a bug

Yes, it is a bug and is related to 16228.  The problem is that
there is a poor implementation of support for the use case
described in that issue, and the details of that implementation
leak out in other use cases.

Ben (in Cc) has a plan to resolve the problem but hasn't had
time to implement it yet.

-Brad