OpenBSD port of dmd?

[Alix Pexton]

I think Walter and Andrei are both right, just about different things.

I think Walter is right that there is no such thing as a default 
implementation when it comes to compatibility with the host environment, 
and asserting is the best course of action.

I think Andrei is right that when a particular environment has some 
advantageous alternate implementation of a feature it can be used while 
leaving the default for the cases where said feature is unavailable.

Walter is concerned with compatibility, Andrei with opportunistic 
optimisation.

Knowing how to tell the difference is the real trick, and that is often 
a much harder thing to pin down. Code that potentially needs to be 
different on every platform should assert when the platform is 
unrecognised. Code which is specialised for just a few platforms and has 
a "known good" default can use else to provide said default. When 
unsure, assert is the more cautious option.

A...