xorg.xorgserver: add cf-private on darwin

    Undefined symbols for architecture x86_64:
      "_NSDefaultRunLoopMode", referenced from:
          _X11ApplicationMain in libXquartz.a(X11Application.o)
      "_OBJC_CLASS_$_NSArray", referenced from:
          objc-class-ref in libXquartz.a(X11Application.o)
          objc-class-ref in libXquartz.a(X11Controller.o)
          objc-class-ref in libxpbproxy.a(x-selection.o)
      "_OBJC_CLASS_$_NSData", referenced from:
          objc-class-ref in libxpbproxy.a(x-selection.o)
      "_OBJC_CLASS_$_NSDictionary", referenced from:
          objc-class-ref in libxpbproxy.a(x-selection.o)
      "_OBJC_CLASS_$_NSMutableArray", referenced from:
          objc-class-ref in libXquartz.a(X11Application.o)
          objc-class-ref in libXquartz.a(X11Controller.o)
      "_OBJC_CLASS_$_NSMutableDictionary", referenced from:
          objc-class-ref in libXquartz.a(X11Application.o)
      "_OBJC_CLASS_$_NSRunLoop", referenced from:
          objc-class-ref in libXquartz.a(X11Application.o)
      "_OBJC_CLASS_$_NSURL", referenced from:
          objc-class-ref in libXquartz.a(X11Application.o)
      "_OBJC_EHTYPE_$_NSException", referenced from:
          GCC_except_table29 in libxpbproxy.a(x-selection.o)
    ld: symbol(s) not found for architecture x86_64