Re: The list of __HAVE macros

[Taylor R Campbell <campbell+netbsd-tech-kern%mumble.net@localhost>]

> Date: Sun, 5 Mar 2023 21:20:55 +0300
> From: Valery Ushakov <uwe%stderr.spb.ru@localhost>
> 
> We don't seem to have(9) a man page that lists all __HAVE_* macros
> that a port may provide.  E.g.
> 
>   $ apropos -M '"__HAVE_PREEMPTION"'
>   cpu_need_resched (9)    context switch notification
> 
> but
> 
>   $ apropos -M '"__HAVE_SIMPLE_MUTEXES"'
>   apropos: No relevant results obtained.
>   Please make sure that you spelled all the terms correctly or try using different keywords.
> 
> I think it might be a good idea to document the list in one place with
> xrefs to the relevant section 9 pages (and to document the options
> there too, e.g. __HAVE_SIMPLE_MUTEXES in mutex(9)).

I agree!  Want to draft a skeleton in share/man/man9, say
portfeatures.9 or something, so we can fill them and xref as needed?