GDC is a GPL implementation of the D compiler which integrates the open source D front end with GCC.
The GNU D Compiler (GDC) project was originally started by David Friedman in 2004 until early 2007 when he disappeared from the D scene, and was no longer able to maintain GDC. Following a revival attempt in 2008, GDC is now under the lead of Iain Buclaw who has been steering the project since 2009 with the assistance of its contributors, without them the project would not have been nearly as successful as it has been.
Documentation on GDC is available from the wiki. Any bugs or issues found with using GDC should be reported at our bugzilla site. For help with GDC, the D.gnu mailing list is the place to go with questions or problems.
Work is currently under way to merge GDC into GCC for the release of 4.9. Any assitance of any sort during this time would be invaluably appreciated. Feel free to contact me via email or message me at #d.gdc on FreeNode.