I've been working on some enhancements to config(8).

I've added a new keyword to the config(8) file grammar - "no" - which
may be used in the follow ways:
	no pseudo-device foo
	no options foo[,bar[,...]]
	no mkoptions foo
	no file-system foo

These are only valid if an appropriate matching config entry has
already been used.

If a declaration would have resulted in extra files being brought
in (e.g "pseudo-device bpf" pulls in bpf.o and bpf_filter.o, with the
latter potentially shared with ppp) and the "no" equivalent follows,
then the extra files won't be brought in if they're now not necessary.
I.e, the sequence
	pseudo-device foo
	no pseudo-device foo
should result in the same kernel compile directory as if neither line
appeared in the configuration file.

The purpose of this is to allow you to easily create custom config
files by including "GENERIC" and then disabling stuff you're not
interested in.

Unless someone suggests (and hopefully implements :) a better way to
solve this problem, I intend to commit the work I have done so far in
the next day or two.


I've also started on "no device foo at bar", but that's a lot trickier
than the others to get "right".

Comments?

Luke.

-- 
Luke Mewburn  <lukem@wasabisystems.com>  http://www.wasabisystems.com
Luke Mewburn     <lukem@netbsd.org>      http://www.netbsd.org
Wasabi Systems - NetBSD hackers for hire
NetBSD - the world's most portable UNIX-like operating system