kernel config

[jb]

Erich Dollansky <erichfreebsdlist <at> ovitrap.com> writes:

> ...  
> Just check how a custom kernel is build. You can then build three
> versions of it. One with nothing, one with the modules you want and one
> with the non-conflicting modules build-in.
> 
> Just read the handbook regarding custom kernels.
> ...

I have already read all docs :-)
The problem is I still do not get it ...

I understand that files sys/conf/NOTES and sys/<arch>/conf/NOTES contain
directive lines like 'device', 'options', 'machine', 'ident', 'maxusers',
'makeoptions'  etc that the user may place in the kernel configuration that she
will run config(8) with.

What is the specific mechanism (directive in GENERIC file, or something else
in GENERIC file or elsewhere) that says build support for cd9660 fs as built-in
and ext2fs as module, or entire kernel as built-in, or entire kernel as
modular (except things that must be built-in, but then what things and where is
this specified) ?
jb