Building 64-bit on Windows

[Sam Izzo]

Hi,

I would like to use GNUstep to build a 64-bit DLL from some Obj-C code. 
I then want to use the DLL in Unity. The Windows installer on the 
download page seems quite old and doesn't have a 64-bit compiler or 
64-bit libobjc as far as I can tell. I've tried to build everything from 
scratch in msys2 with clang but haven't been successful. I can detail 
the problems I've had and exactly what I've tried if that would help 
(I'll just have to run through it all again and make notes).

Is this possible?

Thanks,
Sam