llvm.clang.ffi depends on unix.types, so make it unix only
llvm.clang.ffi depends on unix.types, so make it unix only

bjourne/factor,nicolas-p/factor,bpollack/factor,nicolas-p/factor,slavapestov/factor,bpollack/factor,slavapestov/factor,sarvex/factor-lang,sarvex/factor-lang,AlexIljin/factor,mrjbq7/factor,dch/factor,factor/factor,bpollack/factor,bjourne/factor,dch/factor,nicolas-p/factor,AlexIljin/factor,sarvex/factor-lang,mrjbq7/factor,AlexIljin/factor,AlexIljin/factor,slavapestov/factor,tgunr/factor,factor/factor,mrjbq7/factor,tgunr/factor,tgunr/factor,bjourne/factor,AlexIljin/factor,AlexIljin/factor,sarvex/factor-lang,tgunr/factor,nicolas-p/factor,bjourne/factor,dch/factor,sarvex/factor-lang,mrjbq7/factor,factor/factor,nicolas-p/factor,factor/factor,factor/factor,slavapestov/factor,bpollack/factor,tgunr/factor,bpollack/factor,nicolas-p/factor,dch/factor,mrjbq7/factor,sarvex/factor-lang,dch/factor,bjourne/factor,sarvex/factor-lang,factor/factor,AlexIljin/factor,mrjbq7/factor,slavapestov/factor,slavapestov/factor,slavapestov/factor,bjourne/factor,bpollack/factor,dch/factor,bpollack/factor,bjourne/factor,nicolas-p/factor,tgunr/factor