./../common/xen/io/evtchn_dev.c:637:38: error: cast between incompatible function types from 'void (*)()' to 'uint_t (*)(char *, char *)' {aka 'unsigned int (*)(char *, char *)'} [-Werror=cast-function-type]
  (void) add_avintr(NULL, IPL_EVTCHN, (avfunc)evtchn_device_upcall,
                                      ^
cc1: all warnings being treated as errors