On the code path for builds without 64 bit time_t default syscall, the check to fallback to 32 bit is wrong:

 38   bool need_time64 = abs_timeout != NULL
 39                      && !in_time_t_range (abs_timeout->tv_sec);
 40   if (need_time64)
 41     {
 42       int r = SYSCALL_CANCEL (mq_timedreceive_time64, mqdes, msg_ptr, msg_len,
 43                               msg_prio, abs_timeout);
 44       if (r == 0 || errno != ENOSYS)
 45         return r;
 46       __set_errno (EOVERFLOW);
 47       return -1;
 48     }

It should check if 'r >= 0'.