D calling convention

[Walter Bright]

Jason House wrote:
> It's sounding like right-to-left makes more sense than left-to-right.
> As an English speaker, left-to-right seems more natural, but I see no
> reason to require it.  Beyond that, do we really want to require an
> evaluation order of arguments?  I'd much prefer for the compiler to
> work its optimization magic than have a set order anyway.

People intuitively expect expressions to be evaluated left-to-right, and 
that applies to function arguments, too.

Eliminating implementation defined behavior makes the source code much 
more portable. There is no way to reliably detect inadvertent 
order-of-evaluation dependencies.