Horrible DMD startup performance on Windows

[Bruno Medeiros via Digitalmars-d]

I dunno if this was discussed already (I couldn't find any other thread) 
- but ever since DMD was ported to D, the startup performance on Windows 
has become horrible. Takes over 3 seconds on my machine just to display 
the version.

```
$ time ./dmd.exe --version
DMD32 D Compiler v2.071.0
Copyright (c) 1999-2015 by Digital Mars written by Walter Bright

real    0m3.312s
user    0m0.000s
sys     0m0.015s
```

On Linux (even under a VM), it's instantaneous. LDC is instantaneous 
too. Is this a bug or some architectural/backend limitation of DMD on 
Windows?

-- 
Bruno Medeiros
https://twitter.com/brunodomedeiros