Build on kfreebsd fails due to multiple undefined symbols; see https://buildd.debian.org/status/fetch.php?pkg=pike8.0&arch=kfreebsd-amd...

It seems 6b9645e2708c53e92db4f752490f0d168280db10 introduced a bug among the #ifs in backend.cmod. At then line 2425, now line 2908, it did

-#elif defined(BACKEND_USES_POLL) +#endif /* HAVE_SYS_DEVPOLL_H || HAVE_SYS_EPOLL_H */ + +#ifdef HAVE_POLL

but then later we have

#endif /* HAVE_POLL */

and then

#elif defined(BACKEND_USES_KQUEUE)

which doesn't match up with the other #ifdef BACKEND_USES_* conditionals any longer, so the KQUEUE part incorrectly gets omitted.