GDC release 0.20

[Alexander Panek]

David Friedman wrote:
> Source and binaries here:
> 
> http://sourceforge.net/project/showfiles.php?group_id=154306
> 
> * Updated to DMD 0.177
> * Fixes for synchronized code generation
> * Better support for cross-hosted builds
> * Fixed Bugzilla 307, 375, 403, 575, 578
> * Applied Anders Björklund's MacOS X build patches
> * SkyOS support will return when GCC 4.1.1 is supported.

Finally! Woohoo! \o/