Log Message:
Add support for sets of options where at least one option from each
set must be selected, requested and reviewed by wiz:

PKG_OPTIONS_NONEMPTY_SETS
       This is a list of names of sets of options.  At
       least one option from each set must be selected.
       The options in each set are listed in
       PKG_OPTIONS_SET.<setname>.  Options from the sets
       will be automatically added to PKG_SUPPORTED_OPTIONS.