Porting gdc to a new target (Nios2) any guides out there?

[John Carter via D.gnu]

So for various reasons I see potential to use a gdc on an Altera 
FPGA with a nios2 softcore running embedded linux.

Given gdc on linux exists, gdc arm port exists, gcc nios2 back 
end exists....

Leaves me wondering... how hard could it be to get gdc targetting 
Nios2?

Any "this is how to do these things" type guides out there?