To use ARC:
-Include a non-ARC module in your project with this:
"
//Compile the module where this is called as -fno-objc-arc
#import <Foundation/objc-arc.h>
__setup_arc_hooks__;
"
Also, compile the project with the -fblocks and -fobjc-abi-version=3 flags.

Foundation using clang and optimized now.