[phobos] Deprecation of std.date

[Walter Bright]

Jonathan M Davis wrote:
> When compiling phobos normally, the message only prints once. It's only when 
> building phobos with the unit tests enabled that it gets printed over and over. 
> I get the impression that each module is built and run separately when building 
> and running the unit tests on Linux.

Your impression is correct.

>  If that is indeed the case, then your 
> suggestion doesn't really help, since the problem isn't that the deprecated 
> modules get imported multiple times but rather that they're included in multiple 
> builds.
>
>