security/xinetd: Make it fetchable and fix WWW

Original site is gone but code is still available on github. Changed
WWW to point to github and also consumes source code from there.

I've compared content of current github code and original tarball and it
was just missing one function from xgetloadavg.c, now added using patch.

While here, re-generate patches.

PR: 270345
Reported by: diizzy