[Buildroot] Better package 'howto' documentation - anywhere ?

[MikeW]

I'd be grateful if anyone had a link to details / guidelines
for adding a package containing possibly more than one Library target.

The basic doc with Buildroot only considers one Binary target, and
so there is no involvement with using objects in the Staging directory
(headers and libraries), or with optional targets configured from Menuconfig.

Yes, I can and have looked in other packages, but it would be good
to have a 'vanilla' case, the others seem to have different exceptional
requirements ! (And have been done in slightly different styles.)

Alternatively a more theoretical treatment, that would allow you
to derive the required steps, might be useful.

Thanks,

MikeW