i.e. I copied the GDC distribution onto the latest TDM MinGW64 release (using the bundle installer), and it still complains about missing libgmp-3.dll and libppl_c-4.dll. The former DLL is quite easy to find in MinGW's download repository, but I can't find the latter DLL anywhere.
The latest TDM MinGW64 uses gcc 4.7.1 and recent MinGW GDC releases use GCC 4.6.1. Maybe that is causing the problem? Try using a TDM MinGW64 build that uses GCC 4.6.1.
