How to build GNUstep with Garbage collection?

[Lloyd Dupont]

One other posssible solution to my problem will be to build GNUstep with 
Garbage collection ON.

2 question arises:
1. How could I build GNUstep with Garbage collection?
2. How could be sure my top level object will be recognized as used / not to 
be collected?
Problem is I'm not writting a GNUstep app here, I'm writing a .NET app with 
a managed wrapper around GNUstep and I'm not sure this wrapper will 
correctly inform the GC of the object it uses....

Any tip? hint? link? tutorial? material?
Thanks! :D