libfprint/fpi-poll.c:398:11: warning: The left operand of '==' is a garbage value
        else if (timercmp(&fprint_timeout, &libusb_timeout, <))
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/sys/time.h:162:17: note: expanded from macro 'timercmp'
  (((a)->tv_sec == (b)->tv_sec) ?                                             \
    ~~~~~~~~~~~ ^