We previously used the Spicy plugin's `Spicy::available` to test for
Spicy support. However, having Spicy support does not necessarily mean that we
have built Zeek with its in-tree Spicy analyzers: the Spicy plugin
could have been pulled in from external. The new BIF now reliably
tells us whether the Spicy analyzers are available; its result
corresponds to what `zeek-config --have-spicy-analyzers` returns as
well.
We also move the two current checks over to use this BIF.
(Note: I refrained from renaming the CMake-side `USE_SPICY_ANALYERS`
to `HAVE_SPICY_ANALYZERS`. We should do this eventually for
consistency, but I didn't want to make more changes than necessary
right now.)
As initial examples, this branch ports the Syslog and Finger analyzers
over. We leave the old analyzers in place for now and activate them
iff we compile without any Spicy.
Needs `zeek-spicy-infra` branches in `spicy/`, `spicy-plugin/`,
`CMake/`, and `zeek/zeek-testing-private`.
Note that the analyzer events remain associated with the Spicy plugin
for now: that's where they will show up with `-NN`, and also inside
the Zeekygen documentation.
We switch CMake over to linking the runtime library into the plugin,
vs. at the top-level through object libraries.
