MinGW build fix

src/AsyncNameResolver.cc

@@ -119,7 +119,7 @@ void AsyncNameResolver::process(fd_set* rfdsPtr, fd_set* wfdsPtr)
 
 int AsyncNameResolver::getsock(sock_t* sockets) const
 {
-  return ares_getsock(channel, sockets, ARES_GETSOCK_MAXNUM);
+  return ares_getsock(channel, (int *) sockets, ARES_GETSOCK_MAXNUM);
 }
 
 void AsyncNameResolver::process(ares_socket_t readfd, ares_socket_t writefd)