Where is object_setInstanceVariable() in GNUstep?

[Andreas Hoeschler]

Hi all,

I try to port (move) some code from Cocoa to GNUstep. In the Cocoa .m 
file I have

#import <objc/objc-class.h>

...
         (void)object_setInstanceVariable(controllerObject, [aspect 
cString], targetCarrier);
...

When I complie this on GNUstep, I get

UIOutletAssociation.m:47: warning: implicit declaration of function 
`object_setInstanceVariable'

Where is this function defined in GNUstep?

Thanks a lot in advance,

   Andreas