Version statement

[Walter Bright]

Nick Sabalausky wrote:
> But now, when you or someone else comes along and compiles it for OS_D, it's 
> going to silently use the code for OS_B and OS_C *regardless* of whether or 
> not that's correct for OS_D.

That particular problem has bitten me probably hundreds of times, and every 
other programmer as well. And it happens for lots of things besides OS versions.

Though a programmer can always defeat the intent. At one point, someone added 
"support" for another OS in Phobos by copy/pasting the support declarations from 
another OS into the version block. Naturally, it was all wrong. The problem was 
I didn't know which parts were copy/pasted, so I had to go through every single 
declaration one at a time.