Raising the bar on Phobos unittest coverage

[Walter Bright]

On 3/18/2013 4:08 PM, Jonathan M Davis wrote:
> The normal thing to do with unit tests when you want to have them enabled on
> part of the time is to use a version block. And you have to recompile whenever
> you make changes anyway, so I wouldn't expect it to be a big deal in general.

Also, a unittest executable is built and then run and then deleted. I see no 
point to keeping it around and running it in different ways, hence no real value 
in passing parameters to it via an environment variable.