[phobos] MODEL inference

[Andrei Alexandrescu]

I'm seeing this is phobos/posix.mak:

MODEL:=default
ifneq (default,$(MODEL))
       MODEL_FLAG:=-m$(MODEL)
endif

I find it unpleasant that we have directories 
generated/xxx/yyy/{32,64,default} of which default is identical to another.

Is there a simple and robust technique to detect the default model on a 
given platform?


Thanks,

Andrei